Wavefront reversal of laser radiation with intermediate frequency conversion to a different wavelength range

A method was developed for the reversal of the wavefront of laser radiation suitable for a wide range of wavelengths. It is based on parametric mixing of an input signal with a reference wave and conversion of its frequency to a different (intermediate) frequency range where the reversal takes place. During the return passage through the parametric mixer the reversed intermediatefrequency signal forms, together with the reversed reference wave, radiation at the frequency of the input signal but with the reversed wavefront. This reversal method was tested experimentally for radiation with the wavelength λ = 0.53 μ.