Engineering the Optical Spring via Intra-Cavity Optical-Parametric Amplification

TL;DR

This paper explores how intra-cavity optical-parametric amplification can be used to engineer the optical spring effect in interferometers, enhancing gravitational-wave detector sensitivity by controlling the spectral density through pump phase adjustments.

Contribution

It introduces a method to tune the optical spring effect using intra-cavity optical-parametric amplification with adjustable phase, offering new control over interferometer dynamics.

Findings

The pump phase significantly influences the spectral density of the interferometer.

Intra-cavity optical-parametric amplification enables customizable optical spring effects.

The approach can improve the sensitivity of gravitational-wave detectors.

Abstract

The 'optical spring' results from dynamical back-action and can be used to improve the sensitivity of cavity-enhanced gravitational-wave detectors. The effect occurs if an oscillation of the cavity length results in an oscillation of the intra-cavity light power having such a phase relation that the light's radiation pressure force amplifies the oscillation of the cavity length. Here, we analyse a Michelson interferometer whose optical-spring cavity includes an additional optical-parametric amplifier with adjustable phase. We find that the phase of the parametric pump field is a versatile parameter for shaping the interferometer's spectral density.