Nonlinear optics

Abstract

In the first formulations of nonlinear optics, nonlinear polarizations, nonlinear polarizabilities, and their frequency dependence are described. Then several examples of typical second-order and third-order nonlinear processes are introduced. The phenomena include optical parametric three-wave mixing (second order), four-wave mixing, third-harmonic generation, two-photon absorption, absorption/gain saturation, and phase conjugate wave generation (third order). Short descriptions of nonlinear optical materials are made at the end.