Mapping the nonlinear optical susceptibility by noncollinear second harmonic generation

TL;DR

This paper introduces a noncollinear second harmonic generation method to map the nonlinear optical susceptibility tensor elements without angular scans, demonstrated on Gallium Nitride layers, enabling easier characterization of nonlinear optical properties.

Contribution

The paper presents a novel polarization-based approach to evaluate nonlinear susceptibility tensor elements without angular scans, simplifying the characterization process.

Findings

Successfully applied to Gallium Nitride layers

Can verify Kleinman symmetry applicability

Allows absolute tensor element retrieval from reference measurements

Abstract

We present a method, based on noncollinear second harmonic generation, to evaluate the non-zero elements of the nonlinear optical susceptibility. At a fixed incidence angle, the generated signal is investigated by varying the polarization state of both fundamental beams. The resulting polarization charts allows to verify if Kleinman symmetry rules can be applied to a given material or to retrieve the absolute value of the nonlinear optical tensor terms, from a reference measurement. Experimental measurements obtained from Gallium Nitride layers are reported. The proposed method does not require an angular scan thus is useful when the generated signal is strongly affected by sample rotation