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Physics Today

Melvin Lax

R. R. Alfano, H. Z. Cummins, Myriam P. Sarachik, Joseph L. Birman

Published May 1, 2003• 0 citations
Publisher

Abstract

Melvin Lax, a pioneer in the field of quantum optics, died of cancer on 8 December 2002 at his home in Summit, New Jersey.Born in New York City on 8 March 1922, Lax received his BA in physics from New York University in 1942. He then attended MIT, where he earned two degrees in physics: his SM in 1943 and his PhD in 1947. From 1942 to 1945, he carried out research at the MIT Underwater Sound Laboratory under the direction of Philip M. Morse, Richard H. Bolt, and Herman Feshbach.After receiving his PhD, he took the post of assistant professor of physics at Syracuse University, where he advanced to full professor. In 1955, he joined Bell Telephone Laboratories in Murray Hill, New Jersey, where he worked as a member of the technical staff. During 1962–64, he headed the theoretical physics research department there. He left Bell Labs in 1971 to join the faculty at City College of New York as a Distinguished Professor of Physics, but continued as consultant to Bell Labs’ solid-state electronics research laboratory.Lax’s contributions underlie many aspects of present-day design of optical communication devices. In 1963, he developed a quantum regression theorem and a quantum theory of non-commuting noise sources. His results permitted the calculation of laser spectral line shapes, general photocount distributions, and similar observables. He had a deep and lifelong interest in random processes. Before his death, he had been completing a monograph entitled Random Processes (Oxford U. Press, in press) and had been writing a text on modern quantum optics. He applied the separation of signal and noise to different condensed matter systems. That approach led him to analyze how impurities that are randomly placed in a semiconductor medium or that have randomly varying interaction strength affect the energy levels and hence the medium’s conduction properties. The approach also formed the basis for the so-called coherent potential approximation. Late in life, Lax studied the scattering and transmission of laser light through turbid media such as human tissue. He aimed to devise noninvasive optical diagnostic tools for breast cancer without the drawbacks associated with x-ray use.In 1962, Lax developed a technique to obtain symmetry-related selection rules, including time-reversal, that govern the “go/no-go” alternatives for physical processes—for example, scattering or optical transitions—in crystalline solids. In 1971, with Donald Nelson, he considered the structure of the photoelastic tensor response of a crystal—a problem that had been dormant for more than 80 years—and found that a new physical effect, the antisymmetric microscopic rotations of the atomic constituents, had to be included to explain the experiments. Scientists going back to Friedrich Pockels (in 1893), a founder of the study of optical properties of matter under external fields, had assumed that those effects vanished. As was typical of Lax’s approach, the papers Lax and Nelson subsequently produced were detailed and comprehensive, covering the range from microscopic atomistic force models to macroscopic measurable consequences.The interplay between electronic and vibrational degrees of freedom was a theme that, like random processes, bridged Lax’s earliest work with work he did late in his career. Of particular interest was how that interplay determines the absorption and emission of light and the electrical resistivity of material systems. In his early (1952) papers on the Franck-Condon energy in bulk crystals, he meticulously analyzed the subtle electron-phonon effects. Forty years later, with Wei Cai, he invoked those effects to explain how out-of-equilibrium “hot” electrons and “hot” phonons can interact to give negative carrier mobilities in quantum well, or heterostructure, systems. This was a counterintuitive result.Lax served the physics community in many roles. As a member of the American Physical Society’s publications committee from 1980 to 1982, he was instrumental in helping to create a system for electronic submission and processing of manuscripts. He was ahead of his time in recognizing that he should master computers so he could carry out theoretical physics research. He became so expert in computers that one of his early papers on evaluating Fourier integrals was published in Mathematics of Computation in 1982. He also was on the board of editors of the Physical Review, Quantum Optics , and the International Journal of Modern Physics.In the university setting, Lax had a lasting effect: His students will remember him with admiration, respect, and gratitude. He prepared his lectures with exceptional care; for his advanced courses, he frequently prepared extensive and detailed notes that he himself photocopied and distributed. He gave his time generously to students, colleagues, and others with whom he freely and graciously shared his ideas and insights. He served the City College of New York system on the University Committee on Research, for which he was the university physics liaison.Beyond the campus, Lax served from the mid-1980s as a member of the National Academy of Sciences’ basic research advisory committee, which evaluated research proposals. He provided scientific services also to the Naval Research Laboratory, Los Alamos National Laboratory, the US Army Research Office, and the Department of Energy.In 1999, the Optical Society of America awarded Lax the Willis Lamb Medal for his work in quantum optics. Lax was an irreplaceable member of the CCNY physics department. An eminent physicist with an international reputation, he was also an exceptionally kind and gentle human being and a caring friend. His colleagues share a profound sense of the loss of a unique scientist and are grateful to have had the opportunity to work with him. Melvin Lax PPT|High resolution© 2003 American Institute of Physics.

DOI
10.1063/1.1583545

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Michael Stephen Feld

Ramachandra Rao Dasari, Daniel Kleppner, Charles H. Holbrow

Michael Stephen Feld died in Boston on 10 April 2010, at age 69, after an eight-year struggle with multiple myeloma. He was widely known for his contributions to fundamental laser physics and for pioneering lasers and spectroscopy to biomedical problems.Feld was born 11 November 1940 in Brooklyn, New York. He graduated from Lynbrook High School on Long Island in 1958 and from MIT in 1963 with an SB degree in humanities and sciences and an SM degree in physics. He stayed on at MIT to earn a PhD in physics in 1967 for research on laser spectroscopy under Ali Javan. In 1968 Feld joined the MIT physics department as an assistant professor and went on to a varied and productive career as a member of the physics faculty. Feld’s graduate research laid the foundation for a lifelong interest in quantum optics. He established his presence in that field by demonstrating superradiance—the enhancement by coherence effects of the emission of light from a collection of radiators—in a molecular gas. By pursuing that problem in the face of skeptics who thought that Doppler broadening would make the effect impossible to observe, he demonstrated an independence of thought and scientific determination that would mark his career. His research in quantum optics led Feld into the field of cavity quantum electrodynamics. In 1987 he began a series of experiments on radiative shifts and enhanced and suppressed spontaneous emission of single atoms in an optical resonator. Those culminated in his development of the single-atom laser in 1994.From 1976 until his death, Feld was director of MIT’s Harrison Spectros-copy Laboratory. In that role he fostered collaborations among physicists, chemists, biologists, materials scientists, and physicians by welcoming them to participate in the laboratory. To support cooperative research, he established the MIT Regional Laser Facility, funded by NSF, and the MIT Laser Biomedical Research Center, funded by the National Institutes of Health. One of the research center’s many achievements was the development of the diffraction phase microscope (shown in the photo), which yields nanoscale quantitative measurements of the structure and dynamics of live red blood cells.Feld was notably direct. He questioned with equal intensity, acuteness, and persistence academic administrators, janitors, colleagues, waiters, students, and deliverymen. That quality helped him develop fruitful collaborations with scientists from a wide range of fields. Starting in the 1980s, those collaborations helped him turn his attention increasingly to applying lasers and laser-based techniques to biomedicine and biomedical engineering. Feld was an early leader in the use of light scattering, fluorescence spectroscopy, and Raman spectroscopy to investigate arterial plaque in vivo and to provide early cancer detection in some organs. In recent years his research shifted; rather than use those intensity-based modalities, he used field-based light scattering to develop low-coherence interferometry and to explore how to suppress turbidity and obtain images from inside apparently opaque tissue. Near-IR Raman spectroscopy has made it possible to measure levels of blood glucose through the skin without the prick of a needle. Quantitative phase microscopy has produced three-dimensional maps of the refractive index of live cells free of labels or dyes. It also permits early diagnosis of breast cancer and assessment of whether cells at the margins of a cancerous lesion are themselves cancerous. For his foundational contributions to laser spectroscopy and the biomedical use of spectroscopy, Feld received the 2008 William F. Meggers Award from the Optical Society of America.Throughout his career Feld enthusiastically engaged in undergraduate and graduate teaching at MIT. He supervised more than 50 PhD theses. Reflecting his breadth of interest, they were in chemistry, mechanical engineering, bioengineering, and materials research, as well as in physics, and several were part of the MIT-Harvard Health Sciences and Technology program.The 1963 March on Washington marked the beginning of Feld’s lifelong concern about minority graduate education in physics at MIT. He cochaired the committee that initiated establishment of MIT’s Dr Martin Luther King Jr Visiting Professors Program, and, with characteristic direct action, he personally guided five minority graduate students to their PhD degrees.One of those students was Ronald McNair, who went on to a career as an astronaut. Feld and McNair became close friends, and their teaching was reciprocal: Feld mentored McNair in physics; McNair taught Feld karate. Feld obtained a brown belt and was proud to be outdone by his twin sons, Jonathan and David, who became black belts. As was typical, once Feld became interested in karate, he made a serious study of its physics. He presented widely appreciated talks on the physics of karate with demonstrations that sometimes included his sons; he and McNair coauthored articles on karate. McNair’s death in the space shuttle Challenger accident in 1986 was a deep personal loss for Feld.Michael Feld was a creative, innovative physicist and a man of great charm, always asking for more effort, more time, and more insight from his collaborators and students. Many of them are today advancing laser physics, quantum optics, biomedicine, and biomedical engineering along paths that he opened. Through their work Feld’s already large impact on the scientific community continues to grow.Michael Stephen FeldDONNA COVENEY, MIT MEWS SERVICEPPT|High resolution© 2010 American Institute of Physics.

Physics Today•Nov 1, 2010•0 citations

Hermann Anton Haus, 1925–2003

Jeffrey H. Shapiro

Hermann Anton Haus, an Institute Professor at the Massachusetts Institute of Technology (MIT), was to have been a Keynote Speaker at the Fluctuations and Noise in Photonics and Quantum Optics Conference, from which the papers in this special issue derive. Sadly, on May 21, 2003 – less than two weeks before the conference – Professor Haus succumbed to a heart attack after arriving home in Lexington, Massachusetts, from his regular, 15-mile commute by bicycle from MIT. He was 77. Throughout his lengthy and illustrious career, Professor Haus had repeatedly and very successfully addressed problems of fluctuations and noise, with special focus on the fundamental issues that arise in quantum optics. To honour Professor Haus' legacy to our technical community, this special issue of Journal of Optics B: Quantum and Semiclassical Optics is dedicated to his memory. Professor Haus was born in Ljubljana, Slovenia, in the former Yugoslavia, on 8 August 1925. After attending the Technische Hochschule, Graz, and the Technische Hochschule, Wien, in Austria, he received his Bachelor of Science degree from Union College in Schenectady, New York in 1949. In 1951, he graduated from Rensselaer Polytechnic Institute with a Master of Science in Electrical Engineering, and came to MIT, where he earned his Doctorate of Science and joined the faculty in 1954. He was promoted to Associate Professor in 1958, to Professor in 1962, and to Elihu Thomson Professor in 1973. In 1986, he was conferred the honour of Institute Professor. Professor Haus had a lifelong fascination with noise. While still an undergraduate at Union College, he became aware of Norbert Wiener's theories of statistical phenomena – the new mathematics needed to understand and quantify the random fluctuations we refer to as noise. So it was that noise theory formed the core of Professor Haus' research during the 1950s: noise in electron beams, noise in microwave amplifiers, and noise in amplifier cascades. Two of his notable achievements from that era are his elegant four-terminal impedance transformation for the treatment of noise in electron beams [1], and the single noise measure for optimizing linear amplifier cascades that he developed with Richard B Adler [2]. In 1960 the first working laser was reported, and Professor Haus' noise work shifted from microwaves to higher frequencies – light waves – and to the most fundamental source of fluctuations, the inescapable noise introduced by quantum mechanics. In 1962, he and Charles H Townes used the number-phase uncertainty principle to derive the sensitivity advantage that optical homodyne detection enjoys over optical heterodyne detection [3]. That same year he and James A Mullen tied the fundamental noise limits on linear amplification to the quadrature-noise uncertainty principle [4]. Four years later he and Charles Freed reported the first measurements of photoelectron statistics for a laser operating below and above its oscillation threshold [5]. All three of these works have continuing echoes through more recent research on the quantum theory of coherent detection, the noise limits of phase-insensitive and phase-sensitive amplifiers, and quantum noise measurements via photodetection. It took some time for laser technology to fulfil its initial promise of inexpensive, long-haul, broadband communications, and Professor Haus' work on modelocked, distributed-feedback, and soliton lasers played no small role in that development. Nevertheless, from the 1980s onward, Professor Haus' research interest returned again and again to quantum noise. In collaboration with colleagues from the Raytheon Company he showed that their ring-laser gyroscope was operating at the noise limit set by the number-phase uncertainty principle [6]. In collaboration with Nobuyuki Imoto and Yoshihisa Yamamoto from Nippon Telegraph and Telephone Research Laboratories he proposed a practical route to the quantum nondemolition (QND) measurement of photon number [7]. Together with James P Gordon he elucidated the quantum timing jitter that afflicts soliton propagation down optically-amplified fibre lines [8]. He and Masataka Shirasaki introduced the nonlinear Sagnac loop as a technique for generating squeezed states in optical fibre [9]. Together with his student Yinchieh Lai, Professor Haus established a physically-motivated decomposition that accounts for the various noise contributions seen in soliton squeezing [10]. The impact of these works has continued to reverberate through more recent efforts devoted to optical QND measurements, long-haul soliton transmission systems, and Sagnac loop quantum-noise manipulation. During the last decade of Professor Haus' life, he revisited – in very modern terms – some topics that he had studied early in his career. In a collaboration between his group and researchers at Bell Laboratories he used amplified spontaneous emission noise measurements to accurately predict the performance of a 10-Gbit/s optically-preamplified receiver [11], thus reprising – in the context of broadband optical communications – issues of photodetection noise statistics that he had confronted 30 years earlier with Charles Freed. In an invited paper he described a single noise figure for amplification that is valid from radio to optical frequencies [12], i.e., in both the classical and quantum regimes, thus bringing him back, full circle, to his earliest interest in amplifier noise measures. The culmination of his life's work, however, was his book, Electromagnetic Noise and Quantum Optical Measurements. Published in 2000 [13], it is a distillation of 45 years of his research. Generations of students to come will learn quantum noise from this masterwork. Professor Haus authored or co-authored five books, published more than 300 articles, and presented his work at virtually every major conference and symposium on lasers, quantum electronics, and quantum optics around the world. He was one of very few engineers in the USA to become a member of both the National Academy of Engineering and the National Academy of Sciences. He was a Fellow of the American Academy of Arts and Sciences, the American Physical Society, the Institute of Electrical and Electronics Engineers, and the Optical Society of America. He received Guggenheim and Fulbright Fellowships and several honorary degrees, including one from the University of Vienna, and he received the Austrian government's Wittgenstein Prize for outstanding contributions to humanity. Professor Haus was selected by his MIT colleagues for the 1982–1983 James R Killian Faculty Achievement Award, the highest honour that the MIT faculty bestows. In 1984, the Optical Society of America recognized Professor Haus' contributions with its Frederic Ives Medal, the Society's highest award. In 1995, Professor Haus was awarded the National Medal of Science by President William Jefferson Clinton. In a 1998 interview, Professor Haus was asked about his philosophy of life. He replied, 'Try to do your best, because that's all part of the fun. The greatest thing is that once in a while something clicks. It happens every three of four years. It can't happen more often than that, except for some exceptional people.' Things clicked for Hermann Anton Haus. This happened not just once, not just every three or four years, but regularly and throughout his long career. He was a truly exceptional man. Jeffrey H Shapiro Massachusetts Institute of Technology, Cambridge, USA References [1] Haus H A 1955 Noise in one-dimensional electron beams J. Appl. Phys. 26 560–71 [2] Haus H A and Adler R B 1958 Optimum noise performance of linear amplifiers Proc. IRE 46 1519–33 [3] Haus H A and Townes C H 1962 Comment on `Noise in photoelectric mixing' Proc. IRE 50 1544 [4] Haus H A and Mullen J A 1962 Quantum noise in linear amplifiers Phys. Rev. 128 2407–13 [5] Freed C and Haus H A 1966 Photoelectron statistics produced by a laser operating below and above the threshold of oscillation IEEE J. Quantum Electron. QE-2 190–5 [6] Dorschner T A , Haus H A, Holz M, Smith I W and Statz H 1980 Laser gyro at quantum limit IEEE J. Quantum Electron. QE-16 1376–9 [7] Imoto N, Haus H A and Yamamoto Y 1985 Quantum nondemolition measurement of the photon number via the optical Kerr effect Phys. Rev. A 32 2287-92 [8] Gordon J P and Haus H A 1986 Random walk of coherently amplified solitons in optical fiber transmission Opt. Lett. 11 665–7 [9] Shirasaki M and Haus H A 1990 Squeezing of pulses in a nonlinear interferometer J. Opt. Soc. Am. B 7 30–4 [10] Haus H A and Lai Y 1990 Quantum theory of soliton squeezing: a linearized approach J. Opt. Soc. Am. B 7 386–92 [11] Wong W S, Haus H A, Jiang L A, Hansen P B and Margalit M 1998 Photon statistics of amplified spontaneous emission noise in a 10-Gbit/s optically preamplified direct-detection receiver Opt. Lett. 23 1832–34 [12] Haus H A 2000 Noise figure definition valid from RF to optical frequencies IEEE J. Sel. Topics Quantum Electron. 6 240–7 [13] Haus H A 2000 Electromagnetic Noise and Quantum Optical Measurements (Berlin: Springer)

Journal of Optics B Quantum and Semiclassical Optics•Jul 28, 2004•0 citations

Leonard Mandel

H. Jeff. Kimble, E. Wolf

In the early hours of 9 February 2001, the physics community lost one of its most distinguished members, Leonard Mandel, after a long illness. Mandel was the Lee DuBridge Professor Emeritus of Physics and Optics at the University of Rochester, having become emeritus only a few months before he died, at the age of 73, at his home in Pittsford, New York.Born on 9 May 1927 in Berlin, Germany, where his father had emigrated from Eastern Europe, Mandel received a BSc in mathematics and physics in 1947 and a PhD in nuclear physics in 1951 from Birkbeck College, University of London, in the UK. He became a technical officer at Imperial Chemical Industries Ltd in Welwyn, UK, in 1951. In 1955, he became a lecturer and, later, senior lecturer at Imperial College, University of London. He remained at Imperial College until 1964, when he joined the University of Rochester as a professor of physics. Mandel is widely credited as being one of the founding fathers of the field of quantum optics. Although he made seminal contributions across most of quantum optics, the central theme of his research was the exploration of the nature of light through insightful theoretical analyses and a set of pioneering experiments that have become landmarks in the field. Not since the beginning of quantum mechanics has an individual so intimately investigated and so dramatically advanced our understanding of the quantum aspects of light.Mandel’s early interest in quantum optics was stimulated by the Hanbury Brown–Twiss experiments, in which correlations in the fluctuations of photocurrents from two photodetectors illuminated by light from a distant source reveal information about the spatial coherence properties of the light. Mandel’s entrance into the debate about the appropriate theoretical description of this experiment was a basic paper published in 1958 in the Proceedings of the Physical Society (London) in which the so-called Mandel formula for photoelectric counting made its first appearance.In 1968, Mandel’s research group performed the now famous experiment involving interference at the single photon level: Two beams derived from independent lasers were attenuated to a level such that the average interval between photon emissions was very long compared to the transit time through the apparatus. Interference fringes were nonetheless recorded. As in the Hanbury Brown–Twiss experiment, the detection scheme explored interference of the fourth order in the amplitudes of the fields, as opposed to the more familiar second-order interference (as in a Michelson interferometer, for example), but now with an ingenious extension. Over the next three decades, Mandel continued to refine fourth-order interferometry into a powerful tool for investigating the quantum nature of light. It is now a standard technique used worldwide.Perhaps spurred by the debate about the quantum statistical properties of lasers and other light sources, Mandel and his students were among the first to carry out basic experiments from 1967 to 1968 to elucidate the coherence properties of the laser in the transition from incoherent to coherent emission around threshold. In the ensuing decades, those early studies grew into diverse investigations of more complex laser behavior, including mode correlation and competition in ring lasers, and optical bistability and first-order phase transitions in dye lasers. Mandel played a leading role in the quest to investigate states of the electromagnetic field with manifestly quantum or nonclassical characteristics. In 1977, his group made a historic advance in this endeavor with the first observation of photon anti-bunching in the case of the fluorescent light from a single atom. Subsequently, Mandel and one of his students made the first measurements of another nonclassical effect, namely, sub-Poissonian photon statistics. In the early 1980s, Mandel initiated what would become a landmark set of experiments involving pairs of photons produced by the fission of a pump photon in the process of parametric down conversion. Following earlier work by others on the correlation between photon pairs in atomic cascades, Mandel and his students first demonstrated a key nonclassical aspect of the down conversion process and were able to achieve a localized one-photon state.Pursuing the theme of fourth-order interference with pairs of photons in the late 1980s, Mandel and his students demonstrated quantum spatial beating, violations of local realism, and phase memory due to quantum entanglement with the vacuum. His group showed that P. A. M. Dirac’s well-known statement about single-photon interference must be modified to assert that, in fourth-order interference, a pair of photons interferes only with the pair itself. He and his students also introduced what became known as the Hong-Ou-Mandel interferometer. Beyond what had by then become “the standard model” of manifestly quantum effects, Mandel’s genius for probing the quantum realm led to advances throughout the 1990s that challenged and ultimately redefined our understanding of the quantum character of light and, more generally, of quantum measurement. For example, in 1991, Mandel and his students reported a remarkable experiment involving interference from the superposition of fields from two different but coherent parametric processes. They showed that the mere possibility of making a measurement destroyed an interference pattern, even if this possibility went unrealized. In 1995, Mandel’s group, in an experiment with photon pairs, demonstrated a central tenet of quantum mechanics: that there is no physical reality for elemental quantum processes in the absence of a measurement. Mandel supervised the thesis research of 39 students, many of whom have subsequently become leading figures in science and technology. He earned the lifelong respect of his students for his detailed and conscientious stewardship of their scientific development. He made frequent rounds of his laboratories to interact with each of his students and to provide help ranging from optical alignment and electronic design to theoretical calculations. Not wanting to interrupt a student at work, he would sometimes quietly approach in his soft-soled shoes to view the activity at hand, leading to more than a few startled heart skips. In response to a student’s query, “Can you see a signal yet?” as some component of an apparatus was being aligned, would come his distinctively British reply, “Not a sausage!” Once, when the need arose to regulate the water cooling for an oil diffusion pump, he solved the problem the next morning with a flow switch commandeered from a washing machine at home.In addition to his work at the frontiers of physics, Mandel was an excellent teacher. He had a special interest in neophyte science students and developed the first course at the University of Rochester for non-science majors, which he taught regularly for 20 years. From 1966 to 1995, he was one of the main organizers of a well-known series of international conferences called the Rochester Conferences on Coherence and Quantum Optics. Mandel was the coauthor of Optical Coherence and Quantum Optics (Cambridge U. Press, 1995) and the coeditor of several conference proceedings. In 1980, a paper on coherence properties of optical fields, which he coauthored in 1965, was designated a Citation Classic by the Institute of Scientific Publications. In 1988, that paper was listed as one of the 100 most-cited articles published in the Review of Modern Physics since 1955. Mandel received many top awards, including the Frederic Ives Medal (1993) and the Max Born Medal (1982) from the Optical Society of America. He received the Marconi Medal (1987) from the Italian Research Council and the Thomas Young Award (1989) from the British Institute of Physics. In May 2001, Mandel was elected posthumously to membership in the National Academy of Sciences.Mandel was a scientist with a warm personality, humility, compassion, and a delightful sense of humor. He enjoyed a happy family life with his wife Jeanne, a ballet teacher with whom he shared the love for ballet, and with their two children. He adored his four grandchildren and took lively interest in all their activities. Those of us who were fortunate to have been associated with Mandel as students, colleagues, or friends will remember him with deep affection and utmost respect. He will be greatly missed. Leonard Mandel PPT|High resolution© 2001 American Institute of Physics.

Physics Today•Aug 1, 2001•0 citations

Advances in Laser Physics

Vladilen S Letokhov

Peter Franken was a remarkable man. Immediately after the invention of the laser in 1960, he realized its potentialities for nonlinear effects. His revolutionary paper on second harmonic generation appeared in 1961. It started a revolution in optics, in spite of the fact that some picture editor had removed the spectral spot that was the proof of the effect. Within a few years the experimental field exploded and Bloembergen and collaborators had developed the theory of the new effects to a point that merited his textbook of 1965. Peter Franken turned 70 in 1998 and the traditional Festschrift was prepared. Unfortunately he passed away in 1999, and the book appeared as a dedication to his memory. And a very suitable one it is, because it covers many of the topics he initiated and much of the recent developments following from them. As a long-time friend and colleague, Professor Prokhorov writes the introduction. The book has reviews of topics in nonlinear optics, following their developments up to the late 1990s: Atomic time standards (Ramsay), Femtosecond phenomena at nonlinear optical boundaries (Bloembergen et al ), Nuclear excitation in plasmas (Sobelman) and Raman scattering (Powell and Basiev). Novel fields with strong connections to optics are presented: Quantum interference effects on optical dispersion (Scully et al ), Excitonic features in semiconductor cavities (Gibbs et al ), Nonlinear atom optics (Meystre et al ) and Laser-induced particle emission spectroscopy with atomic resolution (Letokhov). The field mentioned last has been developed by Professor Letokhov in recent years, and I do not know any other place where its methods and potentialities are presented in this detail. The book is a valuable source of information on recent progress in the topics included. It summarizes many important developments of contemporary laser physics. If one wants to get an overview of this research, the book is very valuable. The level of treatment varies a little, from purely descriptive to highly detailed; that is inevitable when many authors are involved. Reading the text requires a certain ability to discern and choose; hence it is no textbook for students. A mature and interested reader, however, can learn much from the book. The most recent developments will, no doubt, become dated, but so much material is central to the field of research that the main part of the text is of lasting value. Groups and individuals working in the area of laser physics will find the volume challenging and useful as a general reference. Here one can look up earlier material and find out its relevance to the most recent progress. Stig Stenholm

Measurement Science and Technology•May 14, 2001•17 citations

Squeeze transformation and optics after Einstein

Young S Kim, Margarita A. Man’ko, Michel R. P. Planat

With this special issue, Journal of Optics B: Quantum and Semiclassical Optics contributes to the celebration of the World Year of Physics held in recognition of five brilliant papers written by Albert Einstein in 1905. There is no need to explain to the readers of this journal the content and importance of these papers, which are cornerstones of modern physics. The 51 contributions in this special issue represent current trends in quantum optics —100 years after the concept of light quanta was introduced. At first glance, in his famous papers of 1905, Einstein treated quite independent subjects—special relativity, the nature and statistical properties of light, electrodynamics of moving bodies and Brownian motion. We now know that all these phenomena are deeply related, and these relations are clearly shown in many papers in this issue. Most of the papers are based on the talks and poster contributions from participants of the 9th International Conference on Squeezed States and Uncertainty Relations (ICSSUR'05), which took place in Besancon, France, 2–6 May, 2005. This was the continuation of a series of meetings, originating with the first workshops organized by Professor Y S Kim at the University of Maryland, College Park, USA, in 1991 and by Professor V I Man'ko at the Lebedev Physical Institute, Moscow in 1992. One of the main topics of ICSSUR'05 and this special issue is the theory and applications of squeezed states and their generalizations. At first glance, one could think that this subject has no relation to Einstein's papers. However, this is not true: the theory of squeezed states is deeply related to special relativity, as far as it is based on the representations of the Lorentz group (see the paper by Kim Y S and Noz M E, S458–S467), which also links the current concepts of entanglement and decoherence with Lorentz-covariance. Besides, studies of the different quantum states of light imply, after all, the study of photon (or photo-electron) statistics and fluctuations of the electromagnetic field, whose importance was first emphasized by Einstein in 1905. The squeezed states can also be considered as a generalization of the concept of coherent states, which turned out to be one of the most important theoretical tools for solving the numerous problems of quantum optics. It seems highly symbolical that the printed version of this special issue will appear in the same month when one of the prominent creators of the theory of coherent states and modern quantum optics—Professor Roy J Glauber—will receive his Nobel Prize in Stockholm. ICSSUR'05 was opened by the invited talk of R J Glauber, `What makes a quantum jump?', and we take great pleasure in congratulating him on this well deserved award. We are sure that all participants of ICSSUR'05 and all readers of this special issue share our feelings. Two other Nobel Prize winners of 2005—Professor J L Hall and Professor T W H\ansch—also made great contributions to quantum optics. In particular, in 1986, J L Hall with collaborators, performed the first experiments on the generation of squeezed states by parametric down conversion, having obtained squeezing at the 50\% level (Wu L A, Kimble H J, Hall J L and Wu H 1986 Phys. Rev. Lett. 57 2520). Another area, which has attracted the attention of many researchers in the past decade and which is well represented in this special issue, is related to the problems of quantum correlations, entanglement and quantum nonlocality. It is also connected with the name of Einstein due to his famous `EPR' paper of 1935 written together with Podolsky and Rosen. For several decades this was an area of `thought experiments' only, but now this field is becoming a new part of physics, known as `quantum information'. The reader can find several papers which introduce new concepts in this area, such as applications of the Galois algebras and discrete Wigner functions. Solutions of different problems of the interaction between light and matter (which also take their origin in Einstein's paper of 1905), stationary and nonstationary Casimir effect, decoherence, new forms of uncertainty relations and their experimental verification, etc, can also be found in this issue. Many other contributions will be published in another special issue of the International Journal of Modern Physics B entitled `Quantum Information in Modern Optics'. This special issue is also the last issue of Journal of Optics B: Quantum and Semiclassical Optics. For the past 15 years this journal and its predecessors—Quantum Optics and Quantum and Semiclassical Optics—gained great respect among the quantum optics community. Many breakthrough papers were published in its pages during this period (see, for example, Schrade G, Man'ko V I, Schleich W P and Glauber R J 1995 Wigner Functions in the Paul trap Quantum Semiclass. Opt. 7 307). Since 1999, Journal of Optics B: Quantum and Semiclassical Optics has published a special issue for each ICSSUR meeting. This is the fourth issue of this series. We would like to thank Institute of Physics Publishing and the staff of Journal of Optics B: Quantum and Semiclassical Optics for providing the opportunity to pursue this programme, hoping that such a cooperation will continue in the future. We would also like to thank the many colleagues, who served as referees and whose efforts helped immensely in the preparation of this issue at such a high standard. The 10th ICSSUR conference will be organized for 2007 in Bradford, UK, by Professor A Vourdas. We invite readers to join us in two years.

Journal of Optics B Quantum and Semiclassical Optics•Nov 22, 2005•2 citations

Lectures on Light

Stephen Colby Rand

This book attempts to bridge the enormous gap between introductory quantum mechanics and the research front of modern optics and scientific fields that make use of light in one step. Hence, while it is suitable as a reference for the specialist in quantum optics, it also targets the nonspecialists from other disciplines who need to understand light and its uses in research. With a unique approach it introduces a single analytic tool, namely the density matrix, to analyze complex optical phenomena encountered in traditional as well as cross‐disciplinary research. It moves swiftly in a tight sequence from elementary to sophisticated topics in quantum optics, including laser tweezers, laser cooling, coherent population transfer, optical magnetism, electromagnetically induced transparency (EIT), squeezed light, and cavity quantum electrodynamics (QED). A systematic approach is used that starts with the simplest systems – stationary two‐level atoms – then introduces atomic motion, adds more energy levels, and moves on to discuss first‐, second‐, and third‐order coherence effects that are the basis for analyzing new optical phenomena in incompletely characterized systems. Unconventional examples and original problems are used to engage even seasoned researchers in exploring a mathematical methodology with which they can tackle virtually any new problem involving light. An extensive bibliography makes connections with mathematical techniques and subject areas which can extend the benefit of each section to guide readers further. The steady progression from “simple” to “elaborate” makes the book accessible not only to students from traditional subject areas that make use of light (physics, chemistry, electrical engineering, and materials science), but also to researchers from the “hyphenated” subjects of modern science and engineering: the biophysicists using mechanical effects of light, photochemists developing coherent control for rare species detection, biomedical engineers imaging through scattering media, electromechanical engineers working on molecular design of materials for electronics and space, electrical and computer engineers developing schemes for quantum computation, cryptography, frequency references, and so on. To try to identify techniques and ideas that are universal enough to be applied across the bewildering landscape of research on intersecting boundaries of emerging modern disciplines is a great challenge of out time. “Lectures on Light” offers selected insights on quantum dynamics and quantum theory of light for exactly this purpose.

Oxford University Press eBooks•May 26, 2010•21 citations
Melvin Lax, a pioneer in the field of quantum optics, died of cancer on 8 December 2002 at his home in Summit, New Jersey.Born in New York City on 8 March 1922, Lax received his BA in physics from New York University in 1942. He then attended MIT, where he earned two degrees in physics: his SM in 1943 and his PhD in 1947. From 1942 to 1945, he carried out research at the MIT Underwater Sound Laboratory under the direction of Philip M. Morse, Richard H. Bolt, and Herman Feshbach.After receiving his PhD, he took the post of assistant professor of physics at Syracuse University, where he advanced to full professor. In 1955, he joined Bell Telephone Laboratories in Murray Hill, New Jersey, where he worked as a member of the technical staff. During 1962–64, he headed the theoretical physics research department there. He left Bell Labs in 1971 to join the faculty at City College of New York as a Distinguished Professor of Physics, but continued as consultant to Bell Labs’ solid-state electronics research laboratory.Lax’s contributions underlie many aspects of present-day design of optical communication devices. In 1963, he developed a quantum regression theorem and a quantum theory of non-commuting noise sources. His results permitted the calculation of laser spectral line shapes, general photocount distributions, and similar observables. He had a deep and lifelong interest in random processes. Before his death, he had been completing a monograph entitled Random Processes (Oxford U. Press, in press) and had been writing a text on modern quantum optics. He applied the separation of signal and noise to different condensed matter systems. That approach led him to analyze how impurities that are randomly placed in a semiconductor medium or that have randomly varying interaction strength affect the energy levels and hence the medium’s conduction properties. The approach also formed the basis for the so-called coherent potential approximation. Late in life, Lax studied the scattering and transmission of laser light through turbid media such as human tissue. He aimed to devise noninvasive optical diagnostic tools for breast cancer without the drawbacks associated with x-ray use.In 1962, Lax developed a technique to obtain symmetry-related selection rules, including time-reversal, that govern the “go/no-go” alternatives for physical processes—for example, scattering or optical transitions—in crystalline solids. In 1971, with Donald Nelson, he considered the structure of the photoelastic tensor response of a crystal—a problem that had been dormant for more than 80 years—and found that a new physical effect, the antisymmetric microscopic rotations of the atomic constituents, had to be included to explain the experiments. Scientists going back to Friedrich Pockels (in 1893), a founder of the study of optical properties of matter under external fields, had assumed that those effects vanished. As was typical of Lax’s approach, the papers Lax and Nelson subsequently produced were detailed and comprehensive, covering the range from microscopic atomistic force models to macroscopic measurable consequences.The interplay between electronic and vibrational degrees of freedom was a theme that, like random processes, bridged Lax’s earliest work with work he did late in his career. Of particular interest was how that interplay determines the absorption and emission of light and the electrical resistivity of material systems. In his early (1952) papers on the Franck-Condon energy in bulk crystals, he meticulously analyzed the subtle electron-phonon effects. Forty years later, with Wei Cai, he invoked those effects to explain how out-of-equilibrium “hot” electrons and “hot” phonons can interact to give negative carrier mobilities in quantum well, or heterostructure, systems. This was a counterintuitive result.Lax served the physics community in many roles. As a member of the American Physical Society’s publications committee from 1980 to 1982, he was instrumental in helping to create a system for electronic submission and processing of manuscripts. He was ahead of his time in recognizing that he should master computers so he could carry out theoretical physics research. He became so expert in computers that one of his early papers on evaluating Fourier integrals was published in Mathematics of Computation in 1982. He also was on the board of editors of the Physical Review, Quantum Optics , and the International Journal of Modern Physics.In the university setting, Lax had a lasting effect: His students will remember him with admiration, respect, and gratitude. He prepared his lectures with exceptional care; for his advanced courses, he frequently prepared extensive and detailed notes that he himself photocopied and distributed. He gave his time generously to students, colleagues, and others with whom he freely and graciously shared his ideas and insights. He served the City College of New York system on the University Committee on Research, for which he was the university physics liaison.Beyond the campus, Lax served from the mid-1980s as a member of the National Academy of Sciences’ basic research advisory committee, which evaluated research proposals. He provided scientific services also to the Naval Research Laboratory, Los Alamos National Laboratory, the US Army Research Office, and the Department of Energy.In 1999, the Optical Society of America awarded Lax the Willis Lamb Medal for his work in quantum optics. Lax was an irreplaceable member of the CCNY physics department. An eminent physicist with an international reputation, he was also an exceptionally kind and gentle human being and a caring friend. His colleagues share a profound sense of the loss of a unique scientist and are grateful to have had the opportunity to work with him. Melvin Lax PPT|High resolution© 2003 American Institute of Physics.
Michael Stephen Feld died in Boston on 10 April 2010, at age 69, after an eight-year struggle with multiple myeloma. He was widely known for his contributions to fundamental laser physics and for pioneering lasers and spectroscopy to biomedical problems.Feld was born 11 November 1940 in Brooklyn, New York. He graduated from Lynbrook High School on Long Island in 1958 and from MIT in 1963 with an SB degree in humanities and sciences and an SM degree in physics. He stayed on at MIT to earn a PhD in physics in 1967 for research on laser spectroscopy under Ali Javan. In 1968 Feld joined the MIT physics department as an assistant professor and went on to a varied and productive career as a member of the physics faculty. Feld’s graduate research laid the foundation for a lifelong interest in quantum optics. He established his presence in that field by demonstrating superradiance—the enhancement by coherence effects of the emission of light from a collection of radiators—in a molecular gas. By pursuing that problem in the face of skeptics who thought that Doppler broadening would make the effect impossible to observe, he demonstrated an independence of thought and scientific determination that would mark his career. His research in quantum optics led Feld into the field of cavity quantum electrodynamics. In 1987 he began a series of experiments on radiative shifts and enhanced and suppressed spontaneous emission of single atoms in an optical resonator. Those culminated in his development of the single-atom laser in 1994.From 1976 until his death, Feld was director of MIT’s Harrison Spectros-copy Laboratory. In that role he fostered collaborations among physicists, chemists, biologists, materials scientists, and physicians by welcoming them to participate in the laboratory. To support cooperative research, he established the MIT Regional Laser Facility, funded by NSF, and the MIT Laser Biomedical Research Center, funded by the National Institutes of Health. One of the research center’s many achievements was the development of the diffraction phase microscope (shown in the photo), which yields nanoscale quantitative measurements of the structure and dynamics of live red blood cells.Feld was notably direct. He questioned with equal intensity, acuteness, and persistence academic administrators, janitors, colleagues, waiters, students, and deliverymen. That quality helped him develop fruitful collaborations with scientists from a wide range of fields. Starting in the 1980s, those collaborations helped him turn his attention increasingly to applying lasers and laser-based techniques to biomedicine and biomedical engineering. Feld was an early leader in the use of light scattering, fluorescence spectroscopy, and Raman spectroscopy to investigate arterial plaque in vivo and to provide early cancer detection in some organs. In recent years his research shifted; rather than use those intensity-based modalities, he used field-based light scattering to develop low-coherence interferometry and to explore how to suppress turbidity and obtain images from inside apparently opaque tissue. Near-IR Raman spectroscopy has made it possible to measure levels of blood glucose through the skin without the prick of a needle. Quantitative phase microscopy has produced three-dimensional maps of the refractive index of live cells free of labels or dyes. It also permits early diagnosis of breast cancer and assessment of whether cells at the margins of a cancerous lesion are themselves cancerous. For his foundational contributions to laser spectroscopy and the biomedical use of spectroscopy, Feld received the 2008 William F. Meggers Award from the Optical Society of America.Throughout his career Feld enthusiastically engaged in undergraduate and graduate teaching at MIT. He supervised more than 50 PhD theses. Reflecting his breadth of interest, they were in chemistry, mechanical engineering, bioengineering, and materials research, as well as in physics, and several were part of the MIT-Harvard Health Sciences and Technology program.The 1963 March on Washington marked the beginning of Feld’s lifelong concern about minority graduate education in physics at MIT. He cochaired the committee that initiated establishment of MIT’s Dr Martin Luther King Jr Visiting Professors Program, and, with characteristic direct action, he personally guided five minority graduate students to their PhD degrees.One of those students was Ronald McNair, who went on to a career as an astronaut. Feld and McNair became close friends, and their teaching was reciprocal: Feld mentored McNair in physics; McNair taught Feld karate. Feld obtained a brown belt and was proud to be outdone by his twin sons, Jonathan and David, who became black belts. As was typical, once Feld became interested in karate, he made a serious study of its physics. He presented widely appreciated talks on the physics of karate with demonstrations that sometimes included his sons; he and McNair coauthored articles on karate. McNair’s death in the space shuttle Challenger accident in 1986 was a deep personal loss for Feld.Michael Feld was a creative, innovative physicist and a man of great charm, always asking for more effort, more time, and more insight from his collaborators and students. Many of them are today advancing laser physics, quantum optics, biomedicine, and biomedical engineering along paths that he opened. Through their work Feld’s already large impact on the scientific community continues to grow.Michael Stephen FeldDONNA COVENEY, MIT MEWS SERVICEPPT|High resolution© 2010 American Institute of Physics.
Hermann Anton Haus, an Institute Professor at the Massachusetts Institute of Technology (MIT), was to have been a Keynote Speaker at the Fluctuations and Noise in Photonics and Quantum Optics Conference, from which the papers in this special issue derive. Sadly, on May 21, 2003 – less than two weeks before the conference – Professor Haus succumbed to a heart attack after arriving home in Lexington, Massachusetts, from his regular, 15-mile commute by bicycle from MIT. He was 77. Throughout his lengthy and illustrious career, Professor Haus had repeatedly and very successfully addressed problems of fluctuations and noise, with special focus on the fundamental issues that arise in quantum optics. To honour Professor Haus' legacy to our technical community, this special issue of Journal of Optics B: Quantum and Semiclassical Optics is dedicated to his memory. Professor Haus was born in Ljubljana, Slovenia, in the former Yugoslavia, on 8 August 1925. After attending the Technische Hochschule, Graz, and the Technische Hochschule, Wien, in Austria, he received his Bachelor of Science degree from Union College in Schenectady, New York in 1949. In 1951, he graduated from Rensselaer Polytechnic Institute with a Master of Science in Electrical Engineering, and came to MIT, where he earned his Doctorate of Science and joined the faculty in 1954. He was promoted to Associate Professor in 1958, to Professor in 1962, and to Elihu Thomson Professor in 1973. In 1986, he was conferred the honour of Institute Professor. Professor Haus had a lifelong fascination with noise. While still an undergraduate at Union College, he became aware of Norbert Wiener's theories of statistical phenomena – the new mathematics needed to understand and quantify the random fluctuations we refer to as noise. So it was that noise theory formed the core of Professor Haus' research during the 1950s: noise in electron beams, noise in microwave amplifiers, and noise in amplifier cascades. Two of his notable achievements from that era are his elegant four-terminal impedance transformation for the treatment of noise in electron beams [1], and the single noise measure for optimizing linear amplifier cascades that he developed with Richard B Adler [2]. In 1960 the first working laser was reported, and Professor Haus' noise work shifted from microwaves to higher frequencies – light waves – and to the most fundamental source of fluctuations, the inescapable noise introduced by quantum mechanics. In 1962, he and Charles H Townes used the number-phase uncertainty principle to derive the sensitivity advantage that optical homodyne detection enjoys over optical heterodyne detection [3]. That same year he and James A Mullen tied the fundamental noise limits on linear amplification to the quadrature-noise uncertainty principle [4]. Four years later he and Charles Freed reported the first measurements of photoelectron statistics for a laser operating below and above its oscillation threshold [5]. All three of these works have continuing echoes through more recent research on the quantum theory of coherent detection, the noise limits of phase-insensitive and phase-sensitive amplifiers, and quantum noise measurements via photodetection. It took some time for laser technology to fulfil its initial promise of inexpensive, long-haul, broadband communications, and Professor Haus' work on modelocked, distributed-feedback, and soliton lasers played no small role in that development. Nevertheless, from the 1980s onward, Professor Haus' research interest returned again and again to quantum noise. In collaboration with colleagues from the Raytheon Company he showed that their ring-laser gyroscope was operating at the noise limit set by the number-phase uncertainty principle [6]. In collaboration with Nobuyuki Imoto and Yoshihisa Yamamoto from Nippon Telegraph and Telephone Research Laboratories he proposed a practical route to the quantum nondemolition (QND) measurement of photon number [7]. Together with James P Gordon he elucidated the quantum timing jitter that afflicts soliton propagation down optically-amplified fibre lines [8]. He and Masataka Shirasaki introduced the nonlinear Sagnac loop as a technique for generating squeezed states in optical fibre [9]. Together with his student Yinchieh Lai, Professor Haus established a physically-motivated decomposition that accounts for the various noise contributions seen in soliton squeezing [10]. The impact of these works has continued to reverberate through more recent efforts devoted to optical QND measurements, long-haul soliton transmission systems, and Sagnac loop quantum-noise manipulation. During the last decade of Professor Haus' life, he revisited – in very modern terms – some topics that he had studied early in his career. In a collaboration between his group and researchers at Bell Laboratories he used amplified spontaneous emission noise measurements to accurately predict the performance of a 10-Gbit/s optically-preamplified receiver [11], thus reprising – in the context of broadband optical communications – issues of photodetection noise statistics that he had confronted 30 years earlier with Charles Freed. In an invited paper he described a single noise figure for amplification that is valid from radio to optical frequencies [12], i.e., in both the classical and quantum regimes, thus bringing him back, full circle, to his earliest interest in amplifier noise measures. The culmination of his life's work, however, was his book, Electromagnetic Noise and Quantum Optical Measurements. Published in 2000 [13], it is a distillation of 45 years of his research. Generations of students to come will learn quantum noise from this masterwork. Professor Haus authored or co-authored five books, published more than 300 articles, and presented his work at virtually every major conference and symposium on lasers, quantum electronics, and quantum optics around the world. He was one of very few engineers in the USA to become a member of both the National Academy of Engineering and the National Academy of Sciences. He was a Fellow of the American Academy of Arts and Sciences, the American Physical Society, the Institute of Electrical and Electronics Engineers, and the Optical Society of America. He received Guggenheim and Fulbright Fellowships and several honorary degrees, including one from the University of Vienna, and he received the Austrian government's Wittgenstein Prize for outstanding contributions to humanity. Professor Haus was selected by his MIT colleagues for the 1982–1983 James R Killian Faculty Achievement Award, the highest honour that the MIT faculty bestows. In 1984, the Optical Society of America recognized Professor Haus' contributions with its Frederic Ives Medal, the Society's highest award. In 1995, Professor Haus was awarded the National Medal of Science by President William Jefferson Clinton. In a 1998 interview, Professor Haus was asked about his philosophy of life. He replied, 'Try to do your best, because that's all part of the fun. The greatest thing is that once in a while something clicks. It happens every three of four years. It can't happen more often than that, except for some exceptional people.' Things clicked for Hermann Anton Haus. This happened not just once, not just every three or four years, but regularly and throughout his long career. He was a truly exceptional man. Jeffrey H Shapiro Massachusetts Institute of Technology, Cambridge, USA References [1] Haus H A 1955 Noise in one-dimensional electron beams J. Appl. Phys. 26 560–71 [2] Haus H A and Adler R B 1958 Optimum noise performance of linear amplifiers Proc. IRE 46 1519–33 [3] Haus H A and Townes C H 1962 Comment on `Noise in photoelectric mixing' Proc. IRE 50 1544 [4] Haus H A and Mullen J A 1962 Quantum noise in linear amplifiers Phys. Rev. 128 2407–13 [5] Freed C and Haus H A 1966 Photoelectron statistics produced by a laser operating below and above the threshold of oscillation IEEE J. Quantum Electron. QE-2 190–5 [6] Dorschner T A , Haus H A, Holz M, Smith I W and Statz H 1980 Laser gyro at quantum limit IEEE J. Quantum Electron. QE-16 1376–9 [7] Imoto N, Haus H A and Yamamoto Y 1985 Quantum nondemolition measurement of the photon number via the optical Kerr effect Phys. Rev. A 32 2287-92 [8] Gordon J P and Haus H A 1986 Random walk of coherently amplified solitons in optical fiber transmission Opt. Lett. 11 665–7 [9] Shirasaki M and Haus H A 1990 Squeezing of pulses in a nonlinear interferometer J. Opt. Soc. Am. B 7 30–4 [10] Haus H A and Lai Y 1990 Quantum theory of soliton squeezing: a linearized approach J. Opt. Soc. Am. B 7 386–92 [11] Wong W S, Haus H A, Jiang L A, Hansen P B and Margalit M 1998 Photon statistics of amplified spontaneous emission noise in a 10-Gbit/s optically preamplified direct-detection receiver Opt. Lett. 23 1832–34 [12] Haus H A 2000 Noise figure definition valid from RF to optical frequencies IEEE J. Sel. Topics Quantum Electron. 6 240–7 [13] Haus H A 2000 Electromagnetic Noise and Quantum Optical Measurements (Berlin: Springer)
In the early hours of 9 February 2001, the physics community lost one of its most distinguished members, Leonard Mandel, after a long illness. Mandel was the Lee DuBridge Professor Emeritus of Physics and Optics at the University of Rochester, having become emeritus only a few months before he died, at the age of 73, at his home in Pittsford, New York.Born on 9 May 1927 in Berlin, Germany, where his father had emigrated from Eastern Europe, Mandel received a BSc in mathematics and physics in 1947 and a PhD in nuclear physics in 1951 from Birkbeck College, University of London, in the UK. He became a technical officer at Imperial Chemical Industries Ltd in Welwyn, UK, in 1951. In 1955, he became a lecturer and, later, senior lecturer at Imperial College, University of London. He remained at Imperial College until 1964, when he joined the University of Rochester as a professor of physics. Mandel is widely credited as being one of the founding fathers of the field of quantum optics. Although he made seminal contributions across most of quantum optics, the central theme of his research was the exploration of the nature of light through insightful theoretical analyses and a set of pioneering experiments that have become landmarks in the field. Not since the beginning of quantum mechanics has an individual so intimately investigated and so dramatically advanced our understanding of the quantum aspects of light.Mandel’s early interest in quantum optics was stimulated by the Hanbury Brown–Twiss experiments, in which correlations in the fluctuations of photocurrents from two photodetectors illuminated by light from a distant source reveal information about the spatial coherence properties of the light. Mandel’s entrance into the debate about the appropriate theoretical description of this experiment was a basic paper published in 1958 in the Proceedings of the Physical Society (London) in which the so-called Mandel formula for photoelectric counting made its first appearance.In 1968, Mandel’s research group performed the now famous experiment involving interference at the single photon level: Two beams derived from independent lasers were attenuated to a level such that the average interval between photon emissions was very long compared to the transit time through the apparatus. Interference fringes were nonetheless recorded. As in the Hanbury Brown–Twiss experiment, the detection scheme explored interference of the fourth order in the amplitudes of the fields, as opposed to the more familiar second-order interference (as in a Michelson interferometer, for example), but now with an ingenious extension. Over the next three decades, Mandel continued to refine fourth-order interferometry into a powerful tool for investigating the quantum nature of light. It is now a standard technique used worldwide.Perhaps spurred by the debate about the quantum statistical properties of lasers and other light sources, Mandel and his students were among the first to carry out basic experiments from 1967 to 1968 to elucidate the coherence properties of the laser in the transition from incoherent to coherent emission around threshold. In the ensuing decades, those early studies grew into diverse investigations of more complex laser behavior, including mode correlation and competition in ring lasers, and optical bistability and first-order phase transitions in dye lasers. Mandel played a leading role in the quest to investigate states of the electromagnetic field with manifestly quantum or nonclassical characteristics. In 1977, his group made a historic advance in this endeavor with the first observation of photon anti-bunching in the case of the fluorescent light from a single atom. Subsequently, Mandel and one of his students made the first measurements of another nonclassical effect, namely, sub-Poissonian photon statistics. In the early 1980s, Mandel initiated what would become a landmark set of experiments involving pairs of photons produced by the fission of a pump photon in the process of parametric down conversion. Following earlier work by others on the correlation between photon pairs in atomic cascades, Mandel and his students first demonstrated a key nonclassical aspect of the down conversion process and were able to achieve a localized one-photon state.Pursuing the theme of fourth-order interference with pairs of photons in the late 1980s, Mandel and his students demonstrated quantum spatial beating, violations of local realism, and phase memory due to quantum entanglement with the vacuum. His group showed that P. A. M. Dirac’s well-known statement about single-photon interference must be modified to assert that, in fourth-order interference, a pair of photons interferes only with the pair itself. He and his students also introduced what became known as the Hong-Ou-Mandel interferometer. Beyond what had by then become “the standard model” of manifestly quantum effects, Mandel’s genius for probing the quantum realm led to advances throughout the 1990s that challenged and ultimately redefined our understanding of the quantum character of light and, more generally, of quantum measurement. For example, in 1991, Mandel and his students reported a remarkable experiment involving interference from the superposition of fields from two different but coherent parametric processes. They showed that the mere possibility of making a measurement destroyed an interference pattern, even if this possibility went unrealized. In 1995, Mandel’s group, in an experiment with photon pairs, demonstrated a central tenet of quantum mechanics: that there is no physical reality for elemental quantum processes in the absence of a measurement. Mandel supervised the thesis research of 39 students, many of whom have subsequently become leading figures in science and technology. He earned the lifelong respect of his students for his detailed and conscientious stewardship of their scientific development. He made frequent rounds of his laboratories to interact with each of his students and to provide help ranging from optical alignment and electronic design to theoretical calculations. Not wanting to interrupt a student at work, he would sometimes quietly approach in his soft-soled shoes to view the activity at hand, leading to more than a few startled heart skips. In response to a student’s query, “Can you see a signal yet?” as some component of an apparatus was being aligned, would come his distinctively British reply, “Not a sausage!” Once, when the need arose to regulate the water cooling for an oil diffusion pump, he solved the problem the next morning with a flow switch commandeered from a washing machine at home.In addition to his work at the frontiers of physics, Mandel was an excellent teacher. He had a special interest in neophyte science students and developed the first course at the University of Rochester for non-science majors, which he taught regularly for 20 years. From 1966 to 1995, he was one of the main organizers of a well-known series of international conferences called the Rochester Conferences on Coherence and Quantum Optics. Mandel was the coauthor of Optical Coherence and Quantum Optics (Cambridge U. Press, 1995) and the coeditor of several conference proceedings. In 1980, a paper on coherence properties of optical fields, which he coauthored in 1965, was designated a Citation Classic by the Institute of Scientific Publications. In 1988, that paper was listed as one of the 100 most-cited articles published in the Review of Modern Physics since 1955. Mandel received many top awards, including the Frederic Ives Medal (1993) and the Max Born Medal (1982) from the Optical Society of America. He received the Marconi Medal (1987) from the Italian Research Council and the Thomas Young Award (1989) from the British Institute of Physics. In May 2001, Mandel was elected posthumously to membership in the National Academy of Sciences.Mandel was a scientist with a warm personality, humility, compassion, and a delightful sense of humor. He enjoyed a happy family life with his wife Jeanne, a ballet teacher with whom he shared the love for ballet, and with their two children. He adored his four grandchildren and took lively interest in all their activities. Those of us who were fortunate to have been associated with Mandel as students, colleagues, or friends will remember him with deep affection and utmost respect. He will be greatly missed. Leonard Mandel PPT|High resolution© 2001 American Institute of Physics.
Peter Franken was a remarkable man. Immediately after the invention of the laser in 1960, he realized its potentialities for nonlinear effects. His revolutionary paper on second harmonic generation appeared in 1961. It started a revolution in optics, in spite of the fact that some picture editor had removed the spectral spot that was the proof of the effect. Within a few years the experimental field exploded and Bloembergen and collaborators had developed the theory of the new effects to a point that merited his textbook of 1965. Peter Franken turned 70 in 1998 and the traditional Festschrift was prepared. Unfortunately he passed away in 1999, and the book appeared as a dedication to his memory. And a very suitable one it is, because it covers many of the topics he initiated and much of the recent developments following from them. As a long-time friend and colleague, Professor Prokhorov writes the introduction. The book has reviews of topics in nonlinear optics, following their developments up to the late 1990s: Atomic time standards (Ramsay), Femtosecond phenomena at nonlinear optical boundaries (Bloembergen et al ), Nuclear excitation in plasmas (Sobelman) and Raman scattering (Powell and Basiev). Novel fields with strong connections to optics are presented: Quantum interference effects on optical dispersion (Scully et al ), Excitonic features in semiconductor cavities (Gibbs et al ), Nonlinear atom optics (Meystre et al ) and Laser-induced particle emission spectroscopy with atomic resolution (Letokhov). The field mentioned last has been developed by Professor Letokhov in recent years, and I do not know any other place where its methods and potentialities are presented in this detail. The book is a valuable source of information on recent progress in the topics included. It summarizes many important developments of contemporary laser physics. If one wants to get an overview of this research, the book is very valuable. The level of treatment varies a little, from purely descriptive to highly detailed; that is inevitable when many authors are involved. Reading the text requires a certain ability to discern and choose; hence it is no textbook for students. A mature and interested reader, however, can learn much from the book. The most recent developments will, no doubt, become dated, but so much material is central to the field of research that the main part of the text is of lasting value. Groups and individuals working in the area of laser physics will find the volume challenging and useful as a general reference. Here one can look up earlier material and find out its relevance to the most recent progress. Stig Stenholm
With this special issue, Journal of Optics B: Quantum and Semiclassical Optics contributes to the celebration of the World Year of Physics held in recognition of five brilliant papers written by Albert Einstein in 1905. There is no need to explain to the readers of this journal the content and importance of these papers, which are cornerstones of modern physics. The 51 contributions in this special issue represent current trends in quantum optics —100 years after the concept of light quanta was introduced. At first glance, in his famous papers of 1905, Einstein treated quite independent subjects—special relativity, the nature and statistical properties of light, electrodynamics of moving bodies and Brownian motion. We now know that all these phenomena are deeply related, and these relations are clearly shown in many papers in this issue. Most of the papers are based on the talks and poster contributions from participants of the 9th International Conference on Squeezed States and Uncertainty Relations (ICSSUR'05), which took place in Besancon, France, 2–6 May, 2005. This was the continuation of a series of meetings, originating with the first workshops organized by Professor Y S Kim at the University of Maryland, College Park, USA, in 1991 and by Professor V I Man'ko at the Lebedev Physical Institute, Moscow in 1992. One of the main topics of ICSSUR'05 and this special issue is the theory and applications of squeezed states and their generalizations. At first glance, one could think that this subject has no relation to Einstein's papers. However, this is not true: the theory of squeezed states is deeply related to special relativity, as far as it is based on the representations of the Lorentz group (see the paper by Kim Y S and Noz M E, S458–S467), which also links the current concepts of entanglement and decoherence with Lorentz-covariance. Besides, studies of the different quantum states of light imply, after all, the study of photon (or photo-electron) statistics and fluctuations of the electromagnetic field, whose importance was first emphasized by Einstein in 1905. The squeezed states can also be considered as a generalization of the concept of coherent states, which turned out to be one of the most important theoretical tools for solving the numerous problems of quantum optics. It seems highly symbolical that the printed version of this special issue will appear in the same month when one of the prominent creators of the theory of coherent states and modern quantum optics—Professor Roy J Glauber—will receive his Nobel Prize in Stockholm. ICSSUR'05 was opened by the invited talk of R J Glauber, `What makes a quantum jump?', and we take great pleasure in congratulating him on this well deserved award. We are sure that all participants of ICSSUR'05 and all readers of this special issue share our feelings. Two other Nobel Prize winners of 2005—Professor J L Hall and Professor T W H\ansch—also made great contributions to quantum optics. In particular, in 1986, J L Hall with collaborators, performed the first experiments on the generation of squeezed states by parametric down conversion, having obtained squeezing at the 50\% level (Wu L A, Kimble H J, Hall J L and Wu H 1986 Phys. Rev. Lett. 57 2520). Another area, which has attracted the attention of many researchers in the past decade and which is well represented in this special issue, is related to the problems of quantum correlations, entanglement and quantum nonlocality. It is also connected with the name of Einstein due to his famous `EPR' paper of 1935 written together with Podolsky and Rosen. For several decades this was an area of `thought experiments' only, but now this field is becoming a new part of physics, known as `quantum information'. The reader can find several papers which introduce new concepts in this area, such as applications of the Galois algebras and discrete Wigner functions. Solutions of different problems of the interaction between light and matter (which also take their origin in Einstein's paper of 1905), stationary and nonstationary Casimir effect, decoherence, new forms of uncertainty relations and their experimental verification, etc, can also be found in this issue. Many other contributions will be published in another special issue of the International Journal of Modern Physics B entitled `Quantum Information in Modern Optics'. This special issue is also the last issue of Journal of Optics B: Quantum and Semiclassical Optics. For the past 15 years this journal and its predecessors—Quantum Optics and Quantum and Semiclassical Optics—gained great respect among the quantum optics community. Many breakthrough papers were published in its pages during this period (see, for example, Schrade G, Man'ko V I, Schleich W P and Glauber R J 1995 Wigner Functions in the Paul trap Quantum Semiclass. Opt. 7 307). Since 1999, Journal of Optics B: Quantum and Semiclassical Optics has published a special issue for each ICSSUR meeting. This is the fourth issue of this series. We would like to thank Institute of Physics Publishing and the staff of Journal of Optics B: Quantum and Semiclassical Optics for providing the opportunity to pursue this programme, hoping that such a cooperation will continue in the future. We would also like to thank the many colleagues, who served as referees and whose efforts helped immensely in the preparation of this issue at such a high standard. The 10th ICSSUR conference will be organized for 2007 in Bradford, UK, by Professor A Vourdas. We invite readers to join us in two years.
This book attempts to bridge the enormous gap between introductory quantum mechanics and the research front of modern optics and scientific fields that make use of light in one step. Hence, while it is suitable as a reference for the specialist in quantum optics, it also targets the nonspecialists from other disciplines who need to understand light and its uses in research. With a unique approach it introduces a single analytic tool, namely the density matrix, to analyze complex optical phenomena encountered in traditional as well as cross‐disciplinary research. It moves swiftly in a tight sequence from elementary to sophisticated topics in quantum optics, including laser tweezers, laser cooling, coherent population transfer, optical magnetism, electromagnetically induced transparency (EIT), squeezed light, and cavity quantum electrodynamics (QED). A systematic approach is used that starts with the simplest systems – stationary two‐level atoms – then introduces atomic motion, adds more energy levels, and moves on to discuss first‐, second‐, and third‐order coherence effects that are the basis for analyzing new optical phenomena in incompletely characterized systems. Unconventional examples and original problems are used to engage even seasoned researchers in exploring a mathematical methodology with which they can tackle virtually any new problem involving light. An extensive bibliography makes connections with mathematical techniques and subject areas which can extend the benefit of each section to guide readers further. The steady progression from “simple” to “elaborate” makes the book accessible not only to students from traditional subject areas that make use of light (physics, chemistry, electrical engineering, and materials science), but also to researchers from the “hyphenated” subjects of modern science and engineering: the biophysicists using mechanical effects of light, photochemists developing coherent control for rare species detection, biomedical engineers imaging through scattering media, electromechanical engineers working on molecular design of materials for electronics and space, electrical and computer engineers developing schemes for quantum computation, cryptography, frequency references, and so on. To try to identify techniques and ideas that are universal enough to be applied across the bewildering landscape of research on intersecting boundaries of emerging modern disciplines is a great challenge of out time. “Lectures on Light” offers selected insights on quantum dynamics and quantum theory of light for exactly this purpose.