KINETIC EFFECTS OF 3-13-PHOTON VELOCITY-TUNED RESONANCES INVESTIGATEDBY A TIME-OF-FLIGHT TECHNIQUE

We have investigated the change in the transverse-velocity distributio n of a beam of metastable argon atoms when crossed by an intense, near -resonant, standing-wave laser field. A time-of-flight technique that provides a better resolution at low velocity than the Doppler fluoresc ence technique used in earlier experiments has been utilized. The effe ct of 3-13-photon velocity-tuned (doppleron) resonances in the mean fo rce acting on the atoms has been studied for various laser-frequency d etunings and truncations of a Gaussian light beam. The experimental re sults have been compared with semiclassical laser cooling theory.