Fundamental studies of the coherence properties of electromagnetic radiation. Final report, 1 February 1963--30 November 1965

Theoretical studies have been made of the quantum mechanical description of coherence in materials such as ferromagnets and superconductors and of electromagnetic radiation. In the latter studies, application has been made to effects of coherence and high power on photodetection. A practical result is that the photon echo measurement is shown to provide a sensitive detector of coherence. Experimental work has been carried out to determine the diffusion coefficients and spin depolarization cross sections of optically pumped alkali vapors in noble buffer gases. A method has been developed to measure the density of cesium vapor as a function of temperature. (Author)Theoretical studies have been made of the quantum mechanical description of coherence in materials such as ferromagnets and superconductors and of electromagnetic radiation. In the latter studies, application has been made to effects of coherence and high power on photodetection. A practical result is that the photon echo measurement is shown to provide a sensitive detector of coherence. Experimental work has been carried out to determine the diffusion coefficients and spin depolarization cross sections of optically pumped alkali vapors in noble buffer gases. A method has been developed to measure the density of cesium vapor as a function of temperature. (Author)

Feb 28, 19660 citations

Depolarization of 6P322 cesium atoms, induced in collisions with noble gases

J. Guiry, L. Krause

Cross sections for relaxation of circular and linear polarization of $6^{2}P_{\frac{3}{2}}$ cesium atoms, induced in collisions with ground-state He, Ne, Ar, and Xe, have been determined by Zeeman scanning techniques. A fluorescence cell containing low-pressure cesium vapor together with a buffer gas was irradiated with circularly or linearly polarized 8521-\AA{} Cs resonance radiation, producing excited and polarized Cs atoms which became depolarized in subsequent collisions with the buffer-gas atoms. The resulting depolarization of the cesium resonance fluorescence was monitored in relation to buffer-gas pressure (0-10 Torr) and to the strength of the ambient magnetic field (0-10 kG). At low fields at which the nuclear spin $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ is coupled to the electronic angular momentum $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$, the measurements yielded depolarization cross sections $Q(\mathrm{circ}.)$ and $Q(\mathrm{lin}.)$ , which agree within experimental error with theoretical values calculated for spin-coupled conditions. At kilogauss fields with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ and $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$ decoupled, the experiments produced cross sections for disorientation and disalignment, which are also in satisfactory agreement with the appropriate theoretical predictions. The results indicate that the nuclear spin has a more pronounced effect on the collisional relaxation of the atomic dipole than of the quadrupole.Cross sections for relaxation of circular and linear polarization of $6^{2}P_{\frac{3}{2}}$ cesium atoms, induced in collisions with ground-state He, Ne, Ar, and Xe, have been determined by Zeeman scanning techniques. A fluorescence cell containing low-pressure cesium vapor together with a buffer gas was irradiated with circularly or linearly polarized 8521-\AA{} Cs resonance radiation, producing excited and polarized Cs atoms which became depolarized in subsequent collisions with the buffer-gas atoms. The resulting depolarization of the cesium resonance fluorescence was monitored in relation to buffer-gas pressure (0-10 Torr) and to the strength of the ambient magnetic field (0-10 kG). At low fields at which the nuclear spin $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ is coupled to the electronic angular momentum $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$, the measurements yielded depolarization cross sections $Q(\mathrm{circ}.)$ and $Q(\mathrm{lin}.)$, which agree within experimental error with theoretical values calculated for spin-coupled conditions. At kilogauss fields with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ and $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$ decoupled, the experiments produced cross sections for disorientation and disalignment, which are also in satisfactory agreement with the appropriate theoretical predictions. The results indicate that the nuclear spin has a more pronounced effect on the collisional relaxation of the atomic dipole than of the quadrupole.

Physical Review ADec 1, 197613 citations

Coherence properties of electromagnetic radiation

Edward L. O’Neill, Lee C. Bradley

During the last week of June 1960, a three-day conference on the coherence properties of electromagnetic radiation was held on the campus of the University of Rochester. Sponsored by the US Air Force, the University of Rochester, and the Optical Society of America, the purpose of the conference was to bring together optical and atomic physicists from this country and abroad to discuss problems of common interest dealing with the question of coherence throughout the electromagnetic spectrum. To a large extent motivation was supplied by a number of controversial and surprising developments in widely separated branches of physics within the last decade. Certainly much of the attention paid to questions of coherence after so many years of its having lain dormant is due in no small measure to the now famous Brown-Twiss experiment (1955) on the correlation in fluctuations of the output currents of two photoelectric detectors exposed to mutually coherent fields of light. The controversy that followed demonstrated clearly the lack of understanding of the statistical properties inherent in the emission, propagation, and detection of radiation. Whether or not one chose to explain the correlation as a natural tendency for bosons to clump or a natural interference effect among Fourier components in the finite spectral width of every natural source (or both) seemed at first to be a question of taste.During the last week of June 1960, a three-day conference on the coherence properties of electromagnetic radiation was held on the campus of the University of Rochester. Sponsored by the US Air Force, the University of Rochester, and the Optical Society of America, the purpose of the conference was to bring together optical and atomic physicists from this country and abroad to discuss problems of common interest dealing with the question of coherence throughout the electromagnetic spectrum. To a large extent motivation was supplied by a number of controversial and surprising developments in widely separated branches of physics within the last decade. Certainly much of the attention paid to questions of coherence after so many years of its having lain dormant is due in no small measure to the now famous Brown-Twiss experiment (1955) on the correlation in fluctuations of the output currents of two photoelectric detectors exposed to mutually coherent fields of light. The controversy that followed demonstrated clearly the lack of understanding of the statistical properties inherent in the emission, propagation, and detection of radiation. Whether or not one chose to explain the correlation as a natural tendency for bosons to clump or a natural interference effect among Fourier components in the finite spectral width of every natural source (or both) seemed at first to be a question of taste.

Physics TodayJun 1, 19616 citations

COHERENCE PROPERTIES OF ELECTROMAGNETIC RADIATION

WANG CHIH-CHIANG

摘要本文的主要目的在综合评述近年来在光的相干性方面研究的成就。表明光子简并度和相干度等在有关问题中起重要作用,诸如干涉、拍频、强度起伏等。由于辐射过程的随机性质,拍频信号的强度由过程的相关度决定;由于光子是玻色子,这就决定了强度起伏中有相关项。从已有实验结果看来,光的相于性完全可从量子力学的基础概念得到解释。 Abstract In this paper, recent advances in the research of coherence properties of electromagnetic radiation are discussed. Using the conception of photon degeneracy and degree of coherence the author is able to explain many problems such as light mixing, intensity fluctuations and the properties of coherent light source. Since the occurrence of radiation process is at random, the intensity of the signal generated by the mixing of different sources can be determined by the correlation of radiation processes as derived in the present paper. Regarding photons as bosons, the phenomena "intensity interferense" is explained as quantum fluctuations. The coherence properties of radiation may thus be interpreted well on the basic conception of quantum machanics. 作者及机构信息王之江 Authors and contacts WANG CHIH-CHIANG 参考文献 [1] 施引文献摘要本文的主要目的在综合评述近年来在光的相干性方面研究的成就。表明光子简并度和相干度等在有关问题中起重要作用,诸如干涉、拍频、强度起伏等。由于辐射过程的随机性质,拍频信号的强度由过程的相关度决定;由于光子是玻色子,这就决定了强度起伏中有相关项。从已有实验结果看来,光的相于性完全可从量子力学的基础概念得到解释。 Abstract In this paper, recent advances in the research of coherence properties of electromagnetic radiation are discussed. Using the conception of photon degeneracy and degree of coherence the author is able to explain many problems such as light mixing, intensity fluctuations and the properties of coherent light source. Since the occurrence of radiation process is at random, the intensity of the signal generated by the mixing of different sources can be determined by the correlation of radiation processes as derived in the present paper. Regarding photons as bosons, the phenomena "intensity interferense" is explained as quantum fluctuations. The coherence properties of radiation may thus be interpreted well on the basic conception of quantum machanics. 作者及机构信息王之江 Authors and contacts WANG CHIH-CHIANG 参考文献 [1] 施引文献

Acta Physica SinicaJan 1, 19631 citation

Study on cross-sections between the fine-structure levels of atomic rubidium

Wei Zhang, Shunyan Wang, Guofei An +6 more

The diode-pumped alkali laser (DPAL) is a new type of high-powered laser sources which has been paid much attention in recent years. The fluorescent spectra can be used to investigate how the collisions between atomic rubidium and various buffer gases are affected when a sealed rubidium vapor cell is pumped by a LD. In this study, the cross sections between the fine-structure levels of atomic rubidium in a vapor cell were first theoretically deduced by using a gas kinetic procedure. And then, the sensitized fluorescence was experimentally obtained by means of a series of spectral measurements. Finally, the influence of the temperature on the cross section between the fine -structure levels of atomic rubidium was studied with the systematical analyses. The results are thought to be helpful for deeply understanding the theoretical characteristics of a DPAL at the atomic physics level.The diode-pumped alkali laser (DPAL) is a new type of high-powered laser sources which has been paid much attention in recent years. The fluorescent spectra can be used to investigate how the collisions between atomic rubidium and various buffer gases are affected when a sealed rubidium vapor cell is pumped by a LD. In this study, the cross sections between the fine-structure levels of atomic rubidium in a vapor cell were first theoretically deduced by using a gas kinetic procedure. And then, the sensitized fluorescence was experimentally obtained by means of a series of spectral measurements. Finally, the influence of the temperature on the cross section between the fine -structure levels of atomic rubidium was studied with the systematical analyses. The results are thought to be helpful for deeply understanding the theoretical characteristics of a DPAL at the atomic physics level.

Fifth International Symposium on Laser Interaction with MatterMar 29, 20190 citations

Some Recent Research on Coherence and Fluctuations of Light

A review is presented of various investigations on coherence and fluctuations of light which have been carried out within the last few years. In particular some of the research carried out at the University of Rochester and related investigations undertaken elsewhere are described. This research is mainly concerned with the following topics: classical and quantum description of higher order coherence effects, photon correlation and coincidence experiments, stellar correlation interferometry, photon bunching, and the determination of the statistical properties of light from photoelectric counting experiments.A review is presented of various investigations on coherence and fluctuations of light which have been carried out within the last few years. In particular some of the research carried out at the University of Rochester and related investigations undertaken elsewhere are described. This research is mainly concerned with the following topics: classical and quantum description of higher order coherence effects, photon correlation and coincidence experiments, stellar correlation interferometry, photon bunching, and the determination of the statistical properties of light from photoelectric counting experiments.

Optica Acta International Journal of OpticsOct 1, 19669 citations

Cross sections for relaxation of circular and linear polarization of

6^{2}P_{\frac{3}{2}}

cesium atoms, induced in collisions with ground-state He, Ne, Ar, and Xe, have been determined by Zeeman scanning techniques. A fluorescence cell containing low-pressure cesium vapor together with a buffer gas was irradiated with circularly or linearly polarized 8521-\AA{} Cs resonance radiation, producing excited and polarized Cs atoms which became depolarized in subsequent collisions with the buffer-gas atoms. The resulting depolarization of the cesium resonance fluorescence was monitored in relation to buffer-gas pressure (0-10 Torr) and to the strength of the ambient magnetic field (0-10 kG). At low fields at which the nuclear spin $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ is coupled to the electronic angular momentum $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$, the measurements yielded depolarization cross sections

Q(\mathrm{circ}.)

and

Q(\mathrm{lin}.)

, which agree within experimental error with theoretical values calculated for spin-coupled conditions. At kilogauss fields with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{I}}$ and $\stackrel{\ensuremath{\rightarrow}}{\mathrm{J}}$ decoupled, the experiments produced cross sections for disorientation and disalignment, which are also in satisfactory agreement with the appropriate theoretical predictions. The results indicate that the nuclear spin has a more pronounced effect on the collisional relaxation of the atomic dipole than of the quadrupole.