Determination of the spatial profiles of all components of the quadratic susceptibility tensor X ~((2)) (z, 2 ω ω, ω) of a one-dimensionally inhomogeneous absorbing medium

摘要

For a one-dimensionally inhomogeneous plate whose linear dielectric properties are also inho- mogeneous and are characterized by a diagonal permittivity tensor, it is proved that the spatial profiles of all components of the complex quadratic susceptibility tensor X ~((2)) (z, 2 ω ω, ω) responsible for the second har- monic generation can be uniquely determined, and an appropriate method is proposed. To implement this method, one should measure the complex coefficient of transformation of a fundamental plane wave incident on the plate into a reflected second-harmonic wave in a certain range of angles of incidence. By varying the plane of incidence of the wave and (or) its polarization and measuring the coefficients of transformation into s- and p-polarized waves of double frequency, one can uniquely determine the spatial profiles of all compo- nents of the quadratic susceptibility tensor. The method involves the measurement of the intensities of the second-harmonic waves generated under special conditions with the use of two auxiliary reference plates and thus allows one to avoid complicated phase measurements.