Sub-SQL Sensitivity via Optical Rigidity in Advanced LIGO Interferometer with Optical Losses

TL;DR

This paper analyzes the optical springs regime in Advanced LIGO, showing that optical losses limit sensitivity improvements but are negligible for planned parameters, enabling sensitivity beyond Standard Quantum Limits.

Contribution

It provides a detailed analysis of optical rigidity effects in the presence of optical losses for Advanced LIGO, demonstrating the regime's practical viability.

Findings

Sensitivity surpasses Standard Quantum Limits with optical springs.

Optical losses impose restrictions but are minimal for planned parameters.

The regime offers potential for enhanced gravitational wave detection sensitivity.

Abstract

The ``optical springs'' regime of the signal-recycled configuration of laser interferometric gravitational-wave detectors is analyzed taking in account optical losses in the interferometer arm cavities. This regime allows to obtain sensitivity better than the Standard Quantum Limits both for a free test mass and for a conventional harmonic oscillator. The optical losses restrict the gain in sensitivity and achievable signal-to-noise ratio. Nevertheless, for parameters values planned for the Advanced LIGO gravitational-wave detector, this restriction is insignificant.