Phase modulation and self-modulation of light in three-photon processes

An analysis shows that phase changes in the phase-matched conversion of the frequency of light in piezoelectric crystals can be utilized in fast-response self-bleachable filters and controlled switches. A one-dimensional steady-state approximation is used to study phase modulation of a weak signal in up or down frequency conversion in a transparent piezoelectric crystal pumped at a fixed level. The same approximation is used in considering phase self-modulation of the pumping radiation under frequency doubling conditions. Dependence of various quantities on the input amplitude are obtained for different degrees of detuning; these quantities are the relative intensity and phase shift of the pumping radiation at the output of a frequency doubler, and the degrees of self-bleaching and bleaching in the case of parametric amplification and frequency addition.