Spectral characteristics of nondegenerate phase-conjugate four-wave mixing in an atomic vapor doublet

Abstract

Nondegenerate phase-conjugate four-wave mixing in a resonance vapor doublet is investigated theoretically. It is shown that in the conjugated wave spectrum there are seven spectral ranges of the effective phase conjugation, two of which occur because of coherent interactions between “unpopulated levels” of doublet and are shifted relative to the pumping frequency on the value of doublet splitting. Tuning of phase conjugation spectral ranges by frequency change of pump between vapor doublet is investigated. It is shown that there are specific pump frequencies at which the spectral pattern of conjugation undergoes qualitative changes. In the case when the pump frequency hits in the middle between doublet, four of seven above-mentioned spectral ranges degenerate into two ones with considerable increase of phase-conjugate reflectivity. Between them there is also a point in which phase-conjugate reflectivity decreases abruptly because of mutual compensation of both doublet levels contributions.