Optomechanical cooling and inertial sensing at low frequencies

TL;DR

This paper introduces a novel low-frequency inertial sensor combining optical cavity readout with mechanical resonators, employing optical feedback cooling and cascaded mechanisms to enhance sensitivity, dynamic range, and cooling efficiency.

Contribution

It proposes an integrated inertial sensor design utilizing optical feedback cooling and cascaded cooling to improve low-frequency sensitivity and dynamic range.

Findings

Achieved high acceleration sensitivity in the sub-Hz regime.

Developed a cascaded cooling mechanism for better cooling efficiency.

Designed a compact, lightweight sensor layout.

Abstract

An inertial sensor design is proposed in this paper to achieve high sensitivity and large dynamic range in the sub-Hz frequency regime. High acceleration sensitivity is obtained by combining optical cavity readout systems with monolithically fabricated mechanical resonators. A high-sensitivity heterodyne interferometer simultaneously monitors the test mass with an extensive dynamic range for low-stiffness resonators. The bandwidth is tuned by optical feedback cooling to the test mass via radiation pressure interaction using an intensity-modulated laser. The transfer gain of the feedback system is analyzed to optimize system parameters towards the minimum cooling temperature that can be achieved. To practically implement the inertial sensor, we propose a cascaded cooling mechanism to improve cooling efficiency while operating at low optical power levels. The overall system layout presents an integrated design that is compact and lightweight.