Gravitational wave astronomy is on a path to increase the sensitivity and bandwidth of their detectors to afford the possibility to study a larger variety of sources and physical processes. The authors present solutions to enhance the sensitivity of a laser interferometric gravitational wave detector in the frequency band of 1-5 kHz using optomechanics-based white light signal recycling technologies, overcoming previous limitations of signal recycling.

Gravitational waves from the neutron star coalescence GW170817 were observed from the inspiral, but not the high frequency postmerger nuclear matter motion. Optomechanical white light signal recycling has been proposed for achieving broadband sensitivity in gravitational wave detectors, but has been reliant on development of suitable ultra-low loss mechanical components. Here we show demonstrated optomechanical resonators that meet loss requirements for a white light signal recycling interferometer with strain sensitivity below 10(-24) Hz(-1/2) at a few kHz. Experimental data for two resonators are combined with analytic models of interferometers similar to LIGO to demonstrate enhancement across a broader band of frequencies versus dual-recycled Fabry-Perot Michelson detectors. Candidate resonators are a silicon nitride membrane acoustically isolated by a phononic crystal, and a single-crystal quartz acoustic cavity. Optical power requirements favour the membrane resonator, while thermal noise performance favours the quartz resonator. Both could be implemented as add-on components to existing detectors.