Reconstruction of the coordinate dependences of quadratic susceptibility tensor $$\hat \chi ^{(2)}$$ (z, ω1 ± ω2; ω1, ±ω2) components for the one-dimensionally inhomogeneous absorbing medium

Abstract

A method for the unambiguous reconstruction of the spatial profiles of all components (except for χ zzz ) of the quadratic susceptibility complex tensor {ie165-2} (z, ω1 + ω2; ω1, ω2), which is responsible for the sumfrequency generation in a one-dimensionally inhomogeneous plate is proposed and proven for the first time. Such reconstruction is possible if the symmetry of the medium provides the diagonal character of the linear permittivity tensor {ie165-3} (z, ω). The procedure involves the measurement of the complex amplitude of the new wave with the frequency ω1 + ω2 that is reflected from the plate for a certain interval of the angles of incidence of the wave with the frequency ω2. The reflected wave results from the nonlinear interaction of the wave with frequency ω2 and the wave with frequency ω1 that exhibits the normal incidence. A similar approach can be used to determine the profiles of the components of the quadratic susceptibility tensor {ie165-4}(z, ω1 − ω2; ω1, − ω2), which is responsible for the difference-frequency generation.