Theoretical study of a new method of compensation of the Doppler effect using light displacements

In this research thesis, the author proposes a new method of compensation of the Doppler effect using displacements of energy levels produced by a quasi-resonant light irradiation. He shows that these displacements generally depend on the projection of the atom velocity along the propagation direction of the laser wave, and may sometimes exactly compensate the Doppler effect on a transition sharing a common level with the transition excited by the laser. After a presentation of this approach, and of some related theoretical issues which must be solved in order to better quantitatively describe the studied effect, the author proposes a solution based on a theoretical formalism of the behaviour of an atom belonging to an atomic jet irradiated by an intense laser wave which is generalised to the case of vapours in order to include the effect of atom movements and of possible collisions. Several types of narrow resonance are identified. The author also shows that this formalism significantly simplifies the study of well known effects such as the dynamic Stark effect or saturated absorption. The author then reports a quantitative study of this new method of compensation of the Doppler effect. Expected line shapes, and orders of magnitude, and experiment feasibility are discussed