Chapter 1 Cooling and Trapping Atoms

Baptiste Allard, Juliette Billy, Michèle Leduc

Laurent Hilico, Martina Knoop

Laurent Hilico, Martina Knoop

Vladilen S Letokhov

Abstract One of the most remarkable achievements of laser control is the manipulation of atomic particles, their velocities, positions, etc., which is referred to as laser cooling and laser trapping . These two effects are interrelated and usually prove effective when used jointly. That this is so one can see by considering as an example the laser cooling of trapped ions and the laser trapping of laser-cooled neutral atoms (Fig. 5.1). The sequences of processes in these two situations are directly opposite. Ions can easily be trapped in an electromagnetic trap of large depth (Paul 1990) and then be cooled for a long time by laser radiation (sideband cooling) (Wineland and Dehmelt 1975; Dehmelt 1990). Neutral atoms are first slowed down and cooled by laser radiation down to millikelvin temperatures, and only then confined in an optical trap. Trapped atoms can further be cooled to microkelvin temperatures. The present chapter and Chapter 6 consider the cooling and trapping of neutral atoms, the present chapter concentrating on their cooling, and Chapter 6 on trapping. But it would be reasonable first to familiarize the reader with the history of the early ideas in this field that eventually led to the advent of a new domain of physics—the physics of ultracold atoms and molecules (Chapters 7 and 8).

Ray LaPierre

In recent decades, it has become possible to trap individual atoms and ions. These methods enable the interaction of light with a cloud of atoms or even with individual atoms. There are three general methods that are widely used to trap atoms or ions: radiation pressure, magnetic dipole forces, and electric dipole forces. In this chapter, the major trapping and cooling techniques are reviewed with an emphasis on the basic physical principles.

Roberto Onofrio, Luca Salasnich