Quantum Enhanced Optomechanical Accelerometers

Optomechanical sensors have gained substantial interest in the study of fundamental physics due to their high sensitivity to forces and accelerations. We present our experimental work on sensitivity-enhanced optomechanical accelerometers using quantum noise reduction techniques. Specifically, we employ squeezed light to combat the shot-noise limit in the approximate frequency range of tens to hundreds of kHz. Moving forward, we plan to combine this approach with back-action evasion techniques to also reduce the radiation pressure noise at lower frequencies (at frequencies on the order of a kHz or below). Our approach uses a two-mode squeezed light source, generated through four-wave mixing in rubidium vapor, to characterize and enhance the performance of highly sensitive accelerometers based on microelectromechanical systems (MEMS). We demonstrate this through a sub-shot-noise phase-sensitive readout scheme. This scheme leverages dual-homodyne detection within a non-linear interferometer, facilitated by the four-wave mixing process in an ⁸⁵Rb vapor cell, to effectively transduce the signal from the accelerometers. With the obtained enhanced sensitivity, i.e., the ability to detect smaller signals due to the reduced noise in the system, we aim to use the quantum-enhanced accelerometers to detect ultra-rare events, including the direct gravitational detection of dark matter.