Optimizing Gravitational-Wave Detector Design for Squeezed Light

TL;DR

This paper introduces a new optimization method for gravitational-wave detectors that enhances robustness against optical errors, aiming to improve quantum noise performance in current and future detectors.

Contribution

It presents a novel optimization approach tailored for gravitational-wave detectors, specifically targeting robustness to optical fabrication and installation errors.

Findings

Optimized arm cavities for reduced scattering loss.

Enhanced squeezing performance despite realistic optical errors.

Potential for significantly improved quantum noise performance.

Abstract

Achieving the quantum noise targets of third-generation detectors will require 10 dB of squeezed-light enhancement as well as megawatt laser power in the interferometer arms - both of which require unprecedented control of the internal optical losses. In this work, we present a novel optimization approach to gravitational-wave detector design aimed at maximizing the robustness to common, yet unavoidable, optical fabrication and installation errors, which have caused significant loss in Advanced LIGO. As a proof of concept, we employ these techniques to perform a two-part optimization of the LIGO A+ design. First, we optimize the arm cavities for reduced scattering loss in the presence of point absorbers, as currently limit the operating power of Advanced LIGO. Then, we optimize the signal recycling cavity for maximum squeezing performance, accounting for realistic errors in the positions and radii of curvature of the optics. Our findings suggest that these techniques can be leveraged to achieve substantially greater quantum noise performance in current and future gravitational-wave detectors.