Speaker
Description
Optically levitated sensors inside a Fabry–Pérot cavity have been proposed for high-frequency gravitational-wave detection, but their optimal configuration exhibits a counterintuitive spatial asymmetry. We provide a fully relativistic derivation of the interaction between a gravitational wave and a levitated object in an optical cavity, demonstrating that the GW response is maximized when the sensor is located near the input mirror. We then explain this asymmetry from multiple gauge perspectives and highlight some important consequences for noise couplings in the experiment. Finally, we consider finite-sized dielectric sensors and show that even with modest dimensions, the dielectric can substantially modify the cavity fields, impacting both the optical trapping frequency and system transfer functions.