Application of stochastic resonance in gravitational-wave interferometer

TL;DR

This paper proposes using stochastic resonance in a nonlinear cavity to enhance the sensitivity of gravitational-wave interferometers, significantly increasing the signal-to-noise ratio for wideband detection.

Contribution

It introduces a novel method of applying stochastic resonance in a nonlinear cavity to improve gravitational-wave interferometer sensitivity, especially for wideband signals.

Findings

SNR gain up to ~10 in wideband detection

Effectiveness diminishes with narrower bandwidths

Method is noise-type independent

Abstract

We investigate novel approach, which improves the sensitivity of gravitational wave (GW) interferometer due to stochastic resonance (SR) phenomenon, performing in additional nonlinear cavity (NC). The NC is installed in the output of interferometer before photodetector, so that optical signal emerging interferometer incidents on the NC and passes through it. Under appropriate circumstances a specific transformation of noisy signal inside the NC takes place, which results in the increase of output signal-to-noise ratio (SNR). As a result optical noisy signal of interferometer becomes less noisy after passing through the NC. The improvement of SNR is especially effective in bistable NC for wideband (several hundreds Hz) detection, when chirp GW signal is detected. Then SNR gain reaches amount ~ 10. When detection bandwidth is narrowed, the influence of SR mechanism gradually disappears, and SNR gain tends to 1. SNR gain also tends to 1 when the NC is gradually transformed to linear cavity. Proposed enhancement of SNR due to the SR is not dependent of noise type, which is prevalent in interferometer. Particularly proposed approach is capable to increase signal-to-displacement noise ratio.