Bound and free waves in non-collinear second harmonic generation

TL;DR

This paper investigates the interplay between bound and free waves in noncollinear second harmonic generation, analyzing how polarization, absorption, and incidence angles influence the interference patterns and power generation.

Contribution

It provides a theoretical framework and polarization mapping method to distinguish bound and free wave interference in noncollinear SHG with absorption effects included.

Findings

Polarization mapping reveals interference between bound and free waves.

Absorption affects the interference pattern and power output.

Theoretical simulations match experimental conditions for coherence length samples.

Abstract

We analyze the relationship between the bound and the free waves in the noncollinear SHG scheme, along with the vectorial conservation law for the different components arising when there are two pump beams impinging on the sample with two different incidence angles. The generated power is systematically investigated, by varying the polarization state of both fundamental beams, while absorption is included via the Herman and Hayden correction terms. The theoretical simulations, obtained for samples which are some coherence length thick show that the resulting polarization mapping is an useful tool to put in evidence the interference between bound and free waves, as well as the effect of absorption on the interference pattern