Optical Cooling and Trapping of Atoms

We discuss in this section cooling and trapping of neutral atoms while the next section will deal with spectroscopy in ion traps. 

A free atom interacting with a laser field experience two different kinds of forces. The first is due to the photon recoil during resonance absorption with subsequent spontaneous emission. This force is often called resonanoe radiation pressure. The second force arises from nonresonant stimulated scattering of photons by atoms and occurs only in fields with a nonvanishing field gradient. Let us at first consider how the spontaneous reooil foroe can be utilized to cool atoms [13.13a]. 

In this section we discuss the new technique of optical cooling, which decreases the velocity of atoms to a small interval around v = 0. Optical cooling down to temperatures of a few microKelvin has been achieved by combining optical and evaporative cooling even the nanoKelvin range was reached. This brought the discovery of quite new phenomena, such as Bose-Einstein condensation or atom-lasers, and atomic fountains. [14.5-14.7]. 

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Optical Cooling and Trapping of Atoms Fig. 9.25 Potential energy of... 

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. 

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