PROBE ABSORPTION-SPECTRUM OF A LASER-DRIVEN ATOM NEAR A PHASE CONJUGATOR

The absorption spectrum for weak radiation of a two-state atom near the surface of a phase-conjugating four-wave mixer has been evaluated. Also included is the option that the atom is illuminated by a near-resonant laser field. In the secular limit with respect to the laser-dressed atomic states the absorption spectrum has two lines, just as for a free atom. The strengths and the widths of these lines depend on the phase-conjugate reflectivity, as well as on the optical parameters. It is shown that increasing the reflectivity drives the atom towards saturation through three-photon processes. Also the driving laser tends to saturate the transition, but it is shown that both mechanisms have a different effect on the absorption profile, and can hence be distinguished experimentally.