Characterisation of the waveplate associated to layers in interferential mirrors

TL;DR

This study characterizes the waveplate properties of layers in interferential mirrors through experimental measurements and computational analysis, achieving unprecedented reflectivity and finesse at 1064 nm.

Contribution

It provides new measurements and a detailed characterization of the waveplate effect in interferential mirrors, including the impact of additional layers.

Findings

Achieved record reflectivity at 1064 nm with finesse of 895,000.

Characterized phase retardation as a function of layer number.

Validated experimental results with computational modeling.

Abstract

In this paper, first we present a review of experimental data corresponding to phase retardation per reflection of interferential mirrors. Then, we report our new measurements on both commercial and tailor-made mirrors. To be able to measure the phase retardation as a function of the number of layers, additional pairs of layers are deposited on some of the mirrors. The results obtained with this special set of mirrors allow us to fully characterise the waveplate associated with the additional pairs of layers. We finally implemented a computational study whose results are compared with the experimental ones. Thanks to the additional layers, we have achieved reflectivity never measured before at $\lambda=1064$~nm, with an associated finesse of $\mathcal{F}=895~000$.