Laser trapping of atoms

After a brief review of our work on optical molasses, we will present schemes for laser trapping of atoms that we are trying. We ako present several schemes for laser cooling atoms to temperatures of 10 % and possibly to 10 Finally, the realization of ultra-cold atoms has opened up the potential for new experiments. We will briefly mention a few areas of research that can be addressed with these atoms. 

The goal of this book is to present in a coherent way the problems of the laser control of matter at the atomic-molecular level, namely, control of the velocity distribution of atoms and molecules (saturation Doppler-free spectroscopy) control of the absolute velocity of atoms (laser cooling) control of the orientation, position, and direction of motion of atoms (laser trapping of atoms, and atom optics) control of the coherent behavior of ultracold (quantum) gases laser-induced photoassociation of cold atoms, photoselective ionization of atoms photoselective multiphoton dissociation of simple and polyatomic molecules (vibrationally or electronically excited) multiphoton photoionization and mass spectrometry of molecules and femtosecond coherent control of the photoionization of atoms and photodissociation of molecules. 

The value of the temperature in eqn (5.3) is nowadays referred to as the Doppler temperature or Doppler cooling limit. At a typical value of the natural hnewidth of an allowed transition 2y = 27t X 10 MHz, the temperature To is of the order of 100 pK. Because of the great promise that laser cooling and subsequent laser trapping of atoms held for laser spectroscopy, researchers at the Institute of Spectroscopy in Troitsk, Russia, launched experiments in this field. By the time the first successful experiment was conducted (Andreyev et al. 1981, 1982), the first theoretical work, summarized in a review of the manipulation of atoms by the light pressure force of a resonant laser (Letokhov and Minogin 1981a), had already been completed. 

Gould P L, Lett P D, Julienne P S, Phillips W D, Thorsheim H R and Weiner J 1988 Observation of assooiative ionization of ultraoold laser-trapped sodium atoms Phys.Rev.Lett. 60 788-91... 

Itano, W.M. Bergquist, J.C. Bollinger, J.J. Wineland, D.J., Laser cooling of trapped ions in Laser Manipulation of Atoms and Ions, Proc. Enrico Fermi Summer School, Course CXVIII, Varenna, Italy, July, 1991, edited by E. Arimondo, W.D. Phillips, and F. 

In this section I hope to show how the sensitivity of laser spectroscopy is exploited to obtain data on very low concentrations of atoms. In particular I will start off by considering a few laser atomic beam studies aimed at measuring optical isotope shifts and show how short-lived nuclei can be studied in this way. I shall also mention how it is possible to beat the natural linewidth and obtain supernatural spectra . The discussion of laser studies at low atomic concentrations then leads me onto consider experiments on laser cooling and trapping of atoms and ions. In this context I will also mention some experiments using the shelved electron idea to detect very weak transitions. Finally, I will say something about Rydberg atoms and the effects of atoms near metallic surfaces. 

St. Chu, J.E. Bjorkholm, A. Ashldn, L. Holberg, A. Cable, Cooling and trapping of atoms with laser light, in Methods of Laser Spectroscopy, ed. by Y. Prior, A. Ben-Reuven, M. Rosenbluth (Plenum, New York, 1986), p. 41... 

C. Salomon, Laser cooling of atoms and ion trapping for frequency standards, in Metrology at the Frontiers of Physics and Technology, ed. by L. Crovini, T.J. Quinn (Noith-HoUand, Amsterdam, 1992), p. 405... 

A whole chapter is devoted to time-resolved spectroscopy including the generation and detection of ultrashort light pulses. The principles of coherent spectroscopy, which have found widespread applications, are covered in a separate chapter. The combination of laser spectroscopy and collision physics, which has given new impetus to the study and control of chemical reactions, has deserved an extra chapter. In addition, more space has been given to optical cooling and trapping of atoms and ions. 

COOLING AND TRAPPING OF ATOMS WITH LASER UGHT... 

This paper is not intended to be a review of the field of laser manipulation of atoms, but rather a snap-shot of the work currently underway at AT T Bell Laboratories. In particular, we will not discuss the elegant magnetic trapping experiments of Phillips and his co-workers.[4] For a review of the earlier work m the field, the reader is referred to the earlier review articles of Ashkin [6] and Letokhov and Minogin [7]. More recent collections of articles in the field can be found in dedicated journal issues edited by Phillips [8] and Meystre and Stenholm [9]. 

The development of techniques for cooling and trapping of atoms has led to great advances in physics, which have already been recognized by two Nobel prizes. In 1997 the prize was jointly awarded to Steven Chu, Claude Cohen-Tannoudji, and William D. Phillips for their developments of methods to cool and trap atoms with laser light [1-3]. In 2001, Eric A. Cornell, Wolfgang Ketterle, and Carl E. Wieman jointly received the Nobel prize for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates [4,5]. 

Gould PL, Lett PD, JuUeime PS, Phifiips WD, Thorsheim HR, Weiner J. (1988) Observation of associative ionization of ultracold laser-trapped sodium atoms. Phys. Rev. Lett. 60 788 791. 

Laser cooling and trapping are further discussed in [9.444]. The 1997 Nobel prize in physics was awarded to Ghu, Cohen-Tarmoudji and Phillips for their contributions to the development of cooling and trapping of atoms. 

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