Accuracy of wavefront reversal in stimulated scattering with a frequency and angular shift

An analysis is made of distortions of the reversed wave in stimulated backscattering of light (backward WFR) caused by frequency and angular shifts of the scattered wave relative to the pump wave. The scattered field is expressed in the form of a series in terms of orthogonalized specklons comprising the reversed pump field and its transverse derivatives. It is found that for backward WFR with a frequency detuning Δω, the Stokes field E_S(r, z) is not closest to the pump field E*_L (r, z) to a field in the shifted plane E*_L (r, z + Δz), where Δz=2Δω/ωg, g is the gain. Similar results are also obtained for an angular shift.