Phase conjugation by two-beam coupling in iron-doped lithium niobate

Abstract

A novel technique using two-beam coupling in photorefractive iron-doped lithium niobate crystal to produce phase conjugate waves has been demonstrated. The phase conjugate of a probe wave is generated by exploiting a second- order change in the susceptibility of the nonlinear medium instead of a change in the thus-order susceptibility as in four-wave mixing. The phase conjugate of the probe beam is formed in the direction of transmission due to the diffraction of the pump wave from a 1800 rotated volume grating that is formed in the crystal.