Measurement of Optical Response of a Detuned Resonant Sideband Extraction Interferometer

TL;DR

This paper measures the optical response of a detuned resonant sideband extraction interferometer with power recycling, demonstrating agreement with theoretical predictions and informing future gravitational wave detector designs.

Contribution

It provides the first detailed measurement of the optical response of a detuned RSE interferometer, validating theoretical models and practical lock acquisition procedures.

Findings

Optical gain peaks at 4 kHz and 41 Hz match predictions.

Reliable lock acquisition procedure established.

Results support advanced LIGO optical configurations.

Abstract

We report on the optical response of a suspended-mass detuned resonant sideband extraction (RSE) interferometer with power recycling. The purpose of the detuned RSE configuration is to manipulate and optimize the optical response of the interferometer to differential displacements (induced by gravitational waves) as a function of frequency, independently of other parameters of the interferometer. The design of our interferometer results in an optical gain with two peaks: an RSE optical resonance at around 4 kHz and a radiation pressure induced optical spring at around 41 Hz. We have developed a reliable procedure for acquiring lock and establishing the desired optical configuration. In this configuration, we have measured the optical response to differential displacement and found good agreement with predictions at both resonances and all other relevant frequencies. These results build confidence in both the theory and practical implementation of the more complex optical configuration being planned for Advanced LIGO.