Abstract
The main aim of this lecture has been to study the generalization of the notion of "optical pumping in velocity space" that occurs for narrow-line Doppler cooling. We have shown how the idea of interference between quantum paths can be exploited to cancel the excitation probability of the atom when it has reached the desired velocity class. We discussed two different schemes, leading to the same statistical laws:
- coherent population trapping, which takes advantage of a light-insensitive coherent superposition of internal states;
- raman cooling, which uses optimized light pulses to velocity-selectively transfer an atom from one sublevel of the fundamental electronic level to another.
