Advancements in optomechanical resonators for novel inertial sensors

Our work in the Laboratory of Space Systems and Optomechanics (LASSO) at Texas A&M University involves using optomechanical resonators coupled with compact, high-precision interferometers to create novel inertial sensors. These resonators are etched from monolithic fused silica, which is known to have very low internal losses, allowing for high mechanical quality factors and low thermal acceleration noise in the test mass. Previous measurements at mTorr pressures have demonstrated Q's of 1.91 x 105, corresponding to estimated thermal acceleration noise floor on the order of 10-10 m s- 2/√Hz for frequencies above 30 mHz. In this pressure regime, gas damping is still the dominant loss mechanism. At sufficiently low pressures such that gas damping is negligible, we anticipate mechanical quality factors of the order of 106 and thermal acceleration noise at levels of 10-11 m s-2/√Hz in the sub-Hz regime. As expected, previous measurements have shown significant ambient vibrations that limit our ability to observe the noise floor of the resonator. Hence, we have developed a dedicated vibration isolation platform to mitigate external disturbances, which consists of a pendulum with a magnetic anti-spring to lower the resonant frequency. Sensors constructed with these resonators would be lightweight and cost-effective, making them promising candidates for field applications in geophysics, navigation, and site exploration.