OPTICAL PHASE-CONJUGATION IN ATOMIC VAPORS

Abstract

We present a brief review of optical phase conjugation by four-wave mixing in atomic vapors. We emphasize the particular properties of vapors for this process. We discuss the case of nearly resonant excitation for two-level atoms, the case of multilevel atoms where the nonlinearity arises from optical pumping and the nearly resonant two-photon excitation. We finally describe the modification of phase-conjugate signals when one goes from the Bragg regime to the Raman-Nath regime and we show how one can achieve a phase-contrast mirror rather than a phase-conjugate mirror in this last case.