A Computational and Experimental Analysis of Higher Order Modes in a Strongly Focusing Optical Cavity

TL;DR

This paper presents a combined computational and experimental approach to analyze higher-order modes in strongly focusing optical cavities, enabling better understanding and modeling of their spectral and intensity profiles.

Contribution

It introduces a new method for optical mode decomposition in near-concentric cavities, improving the accuracy of mode analysis in high-precision optical experiments.

Findings

Successfully reproduces cavity transmission spectra and intensity profiles

Provides a justified approximation framework for mode decomposition

Enhances understanding of mode excitation in strongly focusing cavities

Abstract

Optical cavities operating in the near-concentric regime are the fundamental tools to perform high precision experiments like cavity QED applications. A strong focusing regime unfortunately is prone to excite higher-order modes. Higher-order mode excitation is challenging to avoid for the realistic strong focusing cavities, and if these modes are closely spaced, overall cavity linewidth gets significantly broadened. In this study, a computational method alongside the experiment is provided for the optical mode decomposition into cavity eigenmodes with justified approximations. It is shown that it is possible to recreate the intensity and spectral profile of the cavity transmission, with the provided model. As a result, a more complete treatment of the realistic near-concentric cavities can be done.