Pulling of the frequency of a narrow resonance in an interferometer with a nonlinearly absorbing medium

Theoretical and experimental investigations are reported of the shifts due to the pulling of a reference resonance in an external interferometer with a nonlinear absorber. It is shown that for a fixed interferometer length its tuning relative to the transition frequency results in a large additional shift and asymmetry of a resonance because of a correction due to saturated dispersion of the medium. The shifts are considered for the pulling in a system with noninstantaneous and instantaneous "locking" of an interferometer mode to the radiation frequency.