Low frequency inertial sensing

We present an optomechanical inertial sensor for low frequency applications. This accelerometer is readout optically instead of capacitively, limiting electrostatic noise in the system. It consists of a 5 Hz monolithic fused-silica resonator with an oscillating test mass and a heterodyne interferometer readout. It is designed to be a compact, portable, and cost-effective alternative for highly sensitive inertial sensors at low frequencies. Potential applications include but are not limited to gravimetry, geodesy, and hydrology. The resonator has a measured mechanical quality factor $(Q)$ of 477,000 and an $mQ$ -product of 1200 kg. This high $Q$ factor reduces thermal motion, allowing for a device with a competitive acceleration noise floor.