Brewster cross-polarization

TL;DR

This paper provides a theoretical and experimental analysis of the polarization-resolved intensity distribution of a Gaussian beam reflected at Brewster incidence, revealing the emergence of cross-polarized components with specific spatial modes.

Contribution

It introduces a detailed theoretical model for the cross-polarized component in Brewster reflection and confirms it experimentally, highlighting the quadratic scaling with angular spread.

Findings

Cross-polarized TE component appears at Brewster incidence.

TE mode power scales quadratically with angular spread.

Experimental results confirm the theoretical predictions.

Abstract

We theoretically derive the polarization-resolved intensity distribution of a $TM$-polarized fundamental Gaussian beam reflected by an air-glass plane interface at Brewster incidence. The reflected beam has both a dominant ($TM$) and a cross-polarized ($TE$) component, carried by a $\text{TEM}_{10}$ and a $\text{TEM}_{01}$ Hermite-Gaussian spatial mode, respectively. Remarkably, we find that the $TE$-mode power scales quadratically with the angular spread of the incident beam and it is comparable to the $TM$-mode power. Experimental confirmations of the theoretical results are also presented.