Modeling, fabrication, and readout of compact optomechanical accelerometers

Abstract

High-sensitivity accelerometers are key for many applications including ground-based gravitational wave (GW) detectors, in-situ or satellite gravimetry measurements, and inertial navigation systems. We will present our work on the development of optomechanical accelerometers based on the micro-fabrication of mechanical resonators and their integration with laser interferometers to read out their test mass dynamics under the presence of external accelerations. We will discuss the latest developments on compact millimeter-scale resonators made of fused silica and silicon, optimized for frequencies below 1 kHz and exhibiting low mechanical losses. While fused silica has demonstrated high mechanical quality factors at room temperature, silicon devices perform significantly better at very low temperatures, which is particularly relevant for future ground-based gravitational wave detectors where cryogenic environments will be used to improve the sensitivity of the observatories. We will report on our design, modeling, and fabrication process for the silicon-based resonators and present their characterization by means of highly compact fiber-based Fabry-Perot cavities. © 2023 SPIE.