Entropic measure of directional emissions in microcavity lasers

TL;DR

This paper introduces an entropy-based method to quantify and analyze the directionality of emission in microcavity lasers, providing a robust and versatile measure compared to traditional approaches.

Contribution

It proposes using Shannon entropy of far-field profiles in polar and Cartesian coordinates to measure unidirectionality and emission divergence, improving robustness and applicability.

Findings

Entropy measure effectively quantifies unidirectionality.

Method remains robust against deformation parameter variations.

Applicable to complex emission peak structures.

Abstract

We propose a noble notion of the directional emission in microcavity lasers. First, Shannon entropy of the far-field profiles in the polar coordinate can quantify the degree of unidirectionality of the emission, while previous notions about the unidirectionality can not efficiently measure in the robust range against a variation of the deformation parameter. Second, a divergence angle of the directional emission is defined phenomenologically in terms of full width at half maximum, and it is barely applicable to a complicated peak structure. However, Shannon entropy of semi-marginal probability of the far-field profiles in the cartesian coordinate can present equivalent results, and moreover it is applicable to even the cases with a complicated peak structure of the emission.