Magnetic quenching of time-reversed light in photorefractive diluted magnetic semiconductors

Abstract

Phase conjugation is a nonlinear optical effect 1 involving coherent light beams that interact in a nonlinear optical material to generate a beam that exactly retraces the path and reconstructs the wave front of one of the incident waves, called the probe. This property suggests possible applications for phase conjugation such as beam cleanup in laser systems and distortion compensation for beam propagation in distorting media. 2‐4 An often-used analogy between phase conjugation and the time reversal of light waves 5 is based on the wave-front reversal properties of phase conjugation. In the context of optics, invariance under time reversal produces symmetries in a range of optical processes, as for instance in inelastic light scattering. 6 Time reversal by phase conjugation has been shown to lead to the cancellation of the geometric Berry’s phase. 5 However, the relationship between the time-reversal symmetry of a crystal Hamiltonian and macroscopic optical phenomena, in particular, phase conjugation, has only been tentatively explored. An avenue toward the clarification of the relationship between this fundamental physical property and phase conjugation is suggested by the removal of time-reversal symmetry and lifting of Kramers’ degeneracy of a system upon the application of magnetic fields. The objective of this work is to assess the relationship between time reversal and phase-conjugate light by studying the influence of magnetic fields on phase conjugation.