Speaker
Description
We present the results of ongoing experimental work on a table-top prototype for a stable optomechanical phase-insensitive quantum filter. Recent studies have shown that such filters can increase the bandwidth-sensitivity product of both kilometre-scale GW detectors and table-top systems. Our prototype, the Birmingham quantum amplifier, is based on the optomechanical interaction between a high-Q silicon nitride membrane and a system of two coupled optical cavities with a total length of 6 m. This system will operate in the resolved sideband regime and is expected to enhance the sensitivity of the interferometer in the frequency range of $1-20$ kHz.
Our current objective is to perform a proof-of-principle classical demonstration of the signal amplification provided by this setup, as well as showcase its inherent stability without the need for an external controller. Our recent results, which we will discuss in detail, include the successful installation and frequency stabilisation of a two-metre-long quantum filter cavity, whose eigenmode is coupled to the motion of a commercial silicon nitride membrane with a resonant frequency of 229 kHz.
We also discuss the phase-insensitive sensitivity enhancement potential in future GW detectors, including its robustness to optical loss and complementary use with methods based on squeezed light.
