Abstract Laser cooling is an elegant and important tool that has been useful in many branches of atomic physics. For example, laser cooling has enabled the creation and study of Bose-Einstein condensates of dilute atomic vapors (Anderson et al. 1995, Bradley et al. 1995, Davis et al. 1995) and is a central feature in the latest generation of atomic clocks (Santarelli et al. 1999). The creation of cold atomic gases via laser cooling has provided a new venue in which to study atomic collision processes, nonlinear optical effects, and basic quantum-mechanical phenomena. There are innumerable excellent reviews on this vast subject – good starting points are the Nobel lectures by Chu (1998), Phillips (1998), and Cohen-Tannoudji (1998), as well as the text by Metcalf and Van der Straten (1999).
Abstract Laser cooling is an elegant and important tool that has been useful in many branches of atomic physics. For example, laser cooling has enabled the creation and study of Bose-Einstein condensates of dilute atomic vapors (Anderson et al. 1995, Bradley et al. 1995, Davis et al. 1995) and is a central feature in the latest generation of atomic clocks (Santarelli et al. 1999). The creation of cold atomic gases via laser cooling has provided a new venue in which to study atomic collision processes, nonlinear optical effects, and basic quantum-mechanical phenomena. There are innumerable excellent reviews on this vast subject – good starting points are the Nobel lectures by Chu (1998), Phillips (1998), and Cohen-Tannoudji (1998), as well as the text by Metcalf and Van der Straten (1999).
The past few years have seen remarkable developments in the ability to control atomic motion by optical techniques. Among the key tools that have been developed for this purpose are the techniques of laser cooling, the significance of which was recognized by the award of the 1997 Nobel Prize in Physics to Steven Chu, Claude Cohen-Tannoudji, and William Phillips. These techniques have made it possible to cool atoms to temperatures lower than have been produced in any other physical system - around 10(-8) degrees Kelvin above absolute zero - and to confine those in traps for extended periods of observation.
Forty years ago, twenty years after the discovery of the laser, physicists were developing laser cooling methods for ions trapped in electromagnetic fields.From the 1980s onwards, these techniques were refined and extended to atoms, thanks to the audacity and inventiveness of a generation of pioneering researchers.Actually, it was necessary to succeed simultaneously in trapping and cooling samples of atomic gases in a vacuum at a distance from any wall.Spectacular results followed and extraordinarily low temperatures were quickly reached, very close to absolute zero.The field of "cold atoms" was born, rewarded by successive Nobel prizes, first of which was awarded in 1997 to William D. Phillips, Steven Chu and Claude Cohen-Tannoudji, last in 2022 to Alain Aspect.Gaseous samples of a few thousand to a few billion atoms can be prepared at a few millionths of a degree above absolute zero, which means that the particles move at extremely low speed, of the order of centimetres per second.At these extreme temperatures, the behaviour of matter changes and its properties can only be described using quantum mechanics and the wave properties of particles.New physical phenomena have been discovered and innovations have followed the theoretical and experimental progress of the research.Initially imagined as a wonderful method for perfecting atomic physics, cold atoms have gradually proved to be powerful tools for research in cross-cutting fields of physics, such as condensed matter and even high-energy physics.These atoms are now referred to as 'quantum gases' at such low temperatures that their collective behaviour is modified by the laws of quantum mechanics.
This Second Edition describes the basic design and operation of a variety of types of lasers. It overviews some of the traditional applications of lasers, such as laser printers and laser machining. It also describes an unconventional application of lasers: the cooling and confinement of atoms at very low temperature. Ultracold atoms have a number of possible applications that include study of Bose–Einstein condensates. The book reviews traditional Bose–Einstein condensate experiments, as well as zero-gravity experiments and experiments on quasiparticle condensates. Other applications of ultracold atoms include highly accurate atomic clocks, and their use as a time standard. This research and reference text is aimed at science and engineering professionals as well as upper level undergraduate and graduate physics students. Part of IOP Series in Coherent Sources, Quantum Fundamentals, and Applications. Key features • Provides an overview of the basic principles of lasers and reviews typology and operation. • Summarizes the important applications of lasers. • Covers the basic theory behind Bose–Einstein condensates in an accessible format. • Summarizes historical and recent results of Bose-Einstein condensate experiments.
Beams of atoms and molecules (N.F. Ramsey). Momentum exchange between matter and light (S. Stenholm). Quantum effects in atomic optics (D.F. Walls). New laser cooling mechanisms (C. Cohen-Tannoudji). Laser cooling configurations (G. Nienhuis). Velocity-selective coherent population trapping in one and two dimensions (E. Arimondo). Coupled-pendulum model of the forces on three-level atoms (M. Prentiss et al.). Laser cooling and manipulation of atoms and selected applications (S. Chu). Laser cooling and trapping of neutral atoms (W.D. Phillips). Search for montional quantization of laser-cooled atoms (R. Gupta, S. Padua, T. Bergeman, H. Metcalf). The low (temperature) road toward Bose-Einstein condensation in optically and magnetically trapped cesium atoms (Ch. Monroe, E. Comell, C. Wieman). Manipulation of atoms by laser light (W. Ertmer). Laser manipulation of helium: the limits of the semi-classical description (A. Aspect et al.). Light manipulation of atoms (V.1. Balykin). Atom traps and atom optics (D.E. Pritchard and W. Ketterle). Electromagnetic traps for, charged and neutral particles (W. Paul). Laser cooling of trapped ions (W.M. Itano et al.). High-resolution atomic spectroscopy of laser-cooled ions (D.J. Wineland et al.).
Abstract The invention and development of laser methods for cooling and trapping atoms have led to the advent of the physics of ultracold matter. Low-temperature quantum physics has so far dealt with condensed media, wherein quantum phenomena (superfluidity and superconductivity) usually manifest themselves at temperatures of a few kelvin. Laser cooling and trapping of atoms have made it possible to successively attain millikelvin, microkelvin, and nanokelvin temperatures, at which the de Broglie wavelength of the atoms becomes commensurable with the interatomic separation, even in dilute gases. The interaction of atoms in ultracold dilute gases becomes essentially quantum mechanical. The physics of such quantum gases is more akin to the well-developed physics of condensed matter at low temperatures. It is in essence a boundary field between atomic, laser, and condensed-matter physics. Following the first, pioneering experiments on the Bose–Einstein condensation of alkali-metal atoms, this field has continued to develop at a very fast pace, which can be explained by the vast variety of particles (atoms, isotopes, and molecules) that can be laser cooled and trapped under degeneracy conditions. This is much more than physicists had at their disposal previously (3,4He). Moreover, laser radiation and magnetic fields additionally make it possible to control not only the intrinsic quantum state of the interacting ultracold particle species, but also the interaction of the particles. All this makes the research in the field of quantum gases a great breakthrough, both in atomic–molecular physics and in many-body-interaction physics, which heretofore was the prerogative of low-temperature condensed-matter physics.
In the 1980s the first successful experiments [312] and theory [98], demonstrating that light could be used to cool and confine atoms to submillikelvin temperatures, opened several exciting new chapters in atomic, molecular, and optical (AMO) physics. Atom interferometry [6, 8], matter–wave holography [294], optical lattices [192], and Bose–Einstein condensation in dilute gases [18, 95] all exemplified significant new physics where collisions between atoms cooled with light play a pivotal role. The nature of these collisions has become the subject of intensive study not only because of their importance to these new areas of AMO physics but also because their investigation has led to new insights into how cold collision spectroscopy can lead to precision measurements of atomic and molecular parameters and how radiation fields can manipulate the outcome of a collision itself. As a general orientation Fig. 1.1 shows how a typical atomic de Broglie wavelength varies with temperature and where various physical phenomena situate along the scale. With de Broglie wavelengths on the order of a few thousandths of a nanometer, conventional gas-phase chemistry can usually be interpreted as the interaction of classical nuclear point particles moving along potential surfaces defined by their associated electronic charge distribution. At one time liquid helium was thought to define a regime of cryogenic physics, but it is clear from Fig. 1.1 that optical and evaporative cooling have created “cryogenic” environments below liquid helium by many orders of magnitude.