Time-reversal symmetry in nonlinear optics

摘要

The applicability of time-reversal symmetry to nonlinear optics is discussed,both from macroscopic (Maxwell equations) and microscopic (quantum theoretical)point of view. We find that only spatial operations can be applied for thesymmetry classification of nonlinear optical processes in magnetic, inparticular antiferromagnetic, materials. An example is given where bothoperations (time reversal and a spatial operation) can yield different results.