Abstract
In this lecture, we have studied the possibility of manipulating atoms with a narrow line, i.e. such that the natural width of the excited level is smaller than the recoil energy associated with the absorption or emission of a single photon. This question is now highly relevant from an experimental point of view: atoms with two outer electrons are of great interest, particularly from a metrological point of view. These atoms naturally have narrow resonance lines, which couple the sector where the total spin of the two outer electrons is zero (spin singlet) with the sector where the spin is 1 (spin triplet). In this case, the absorption or emission of a single photon is enough to significantly change the atom's saturation parameter, and we can no longer adopt a "continuous Brownian motion" approach. We have therefore switched to a motion description in which each quantum jump is taken into account in a discrete manner. We showed that the stationary distribution has a minimum width given by the recoil velocity. We ended this lecture by describing an experiment recently carried out in Innsbruck, in which the Bose-Einstein condensation threshold was reached directly by narrow-line light cooling.
