On fundamental diffraction limitation of finesse of a Fabry-Perot cavity

TL;DR

This paper investigates the fundamental diffraction limits on the finesse of Fabry-Perot cavities caused by mirror imperfections and asymmetries, introducing a versatile numerical simulation method for eigenmode analysis.

Contribution

It presents a new numerical technique for analyzing eigenmodes and diffraction losses in Fabry-Perot cavities with arbitrary mirror shapes and asymmetries.

Findings

Numerical and analytical results agree for conventional cavities.

The method applies to non-spherical, asymmetric mirror configurations.

Diffraction losses are quantified considering mirror imperfections.

Abstract

We perform a theoretical study of finesse limitations of a Fabry-Perot (FP) cavity occurring due to finite size, asymmetry, as well as imperfections of the cavity mirrors. A method of numerical simulations of the eigenvalue problem applicable for both the fundamental and high order cavity modes is suggested. Using this technique we find spatial profile of the modes and their round-trip diffraction loss. The results of the numerical simulations and analytical calculations are nearly identical when we consider a conventional FP cavity. The proposed numerical technique has much broader applicability range and is valid for any FP cavity with arbitrary non-spherical mirrors which have cylindrical symmetry but disturbed in an asymmetric way, for example, by tilt or roughness of their mirrors.