Experimental demonstration of higher-order Laguerre-Gauss mode interferometry

TL;DR

This paper experimentally demonstrates that higher-order LG33 modes can be effectively used in interferometry, showing comparable error signals to fundamental modes and achieving high mode purity, which is promising for gravitational wave detection.

Contribution

First experimental validation of LG33 mode performance in optical resonators, including control and purity enhancement, relevant for advanced interferometric applications.

Findings

LG33 mode's error signal matches LG00 in linear resonators

Mode purity of LG33 increased from 51% to 99% after resonator transmission

Triangular resonators do not transmit helical LG modes

Abstract

The compatibility of higher-order Laguerre-Gauss (LG) modes with interferometric technologies commonly used in gravitational wave detectors is investigated. In this paper we present the first experimental results concerning the performance of the LG33 mode in optical resonators. We show that the Pound-Drever-Hall error signal for a LG33 mode in a linear optical resonator is identical to that of the more commonly used LG00 mode, and demonstrate the feedback control of the resonator with a LG33 mode. We succeeded to increase the mode purity of a LG33 mode generated using a spatial-light modulator from 51% to 99% upon transmission through a linear optical resonator. We further report the experimental verification that a triangular optical resonator does not transmit helical LG modes.