Displacement-noise-free gravitational-wave detection with two Fabry-Perot cavities

TL;DR

This paper introduces a novel gravitational-wave detector model using two detuned Fabry-Perot cavities that effectively eliminate displacement noise from test masses, enhancing low-frequency sensitivity.

Contribution

It presents a new displacement-noise-free GW detection scheme with a linear combination of signals that cancels mirror noise, outperforming recent proposals at low frequencies.

Findings

Mirror displacement noise can be fully canceled in the combined output.

The proposed model shows stronger low-frequency response than recent interferometer designs.

The approach is demonstrated with a simplified round trip model.

Abstract

We propose two detuned Fabry-Perot cavities, each pumped through both the mirrors, positioned in line as a toy model of the gravitational-wave (GW) detector free from displacement noise of the test masses. It is demonstrated that the noise of cavity mirrors can be completely excluded in a proper linear combination of the cavities output signals. This model is illustrated by a simplified round trip model (without Fabry-Perot cavities). We show that in low-frequency region the obtained displacement-noise-free response signal is stronger than the one of the interferometer recently proposed by S.Kawamura and Y.Chen.