Two-photon resonance in a standing-wave field under conditions of longitudinal interaction with an atomic beam

An analysis is made of the feasibility of obtaining two-photon absorption resonances of 10-100 Hz width under conditions of longitudinal interaction with a standing-wave field. The long atom– field interaction time makes it possible to increase the resonance intensity. It is established that in a system with a beam of atoms propagating along an optical beam, the contribution of slow atoms results in the formation in the second derivative of the line profile of a resonance characteristic with a radiative width. An analysis is made of the influence of the quadratic Doppler effect, Stark effect, and saturation.