ABSTRACT
The study of the motion of neutral atoms under the action of light fields dates back to work of Albert Einstein published as early as 1916. This chapter describes a sample of molecules subjected to a thermal light field. It discusses atoms having only two levels at some optical energy separation. The chapter also discusses radiation pressure in two important examples of light fields, plane travelling and plane standing waves. The two-level atom interacting with a monochromatic laser mode represents one of the most fundamental models in quantum optics and has been extensively studied. The light-shift is an important phenomenon at the basis of many laser cooling mechanisms. In the presence of interaction, the combined system of an ‘atom plus light-field’ is often referred to as the ‘dressed atom’. The steady state temperature in Equation represents the minimum temperature that can be achieved with radiation pressure cooling and can be quite small.
