Single-element dual-interferometer for precision inertial sensing

TL;DR

The paper introduces a compact, high-precision inertial sensor using a novel dual-interferometer design with deep frequency modulation, achieving sub-picometer accuracy suitable for space and ground-based gravitational experiments.

Contribution

It presents the SEDI sensor topology that integrates two interferometers in one optic, simplifying optical setup and enhancing precision for inertial sensing.

Findings

Sub-picometer precision above 10 mHz frequency range.

Feasibility of sub-picometer accuracy down to 2 mHz with two devices.

Compact design suitable for space and ground applications.

Abstract

Tracking moving masses in several degrees of freedom with high precision and large dynamic range is a central aspect in many current and future gravitational physics experiments. Laser interferometers have been established as one of the tools of choice for such measurement schemes. Using sinusoidal phase modulation homodyne interferometry allows a drastic reduction of the complexity of the optical setup, a key limitation of multi-channel interferometry. By shifting the complexity of the setup to the signal processing stage, these methods enable devices with a size and weight not feasible using conventional techniques. In this paper we present the design of a novel sensor topology based on deep frequency modulation interferometry: the self-referenced single-element dual-interferometer (SEDI) inertial sensor, which takes simplification one step further by accommodating two interferometers in one optic. Using a combination of computer models and analytical methods we show that an inertial sensor with sub-picometer precision for frequencies above 10 mHz, in a package of a few cubic inches, seems feasible with our approach. Moreover we show that by combining two of these devices it is possible to reach sub-picometer precision down to 2 mHz. In combination with the given compactness, this makes the SEDI sensor a promising approach for applications in high precision inertial sensing for both next-generation space-based gravity missions employing drag-free control, and ground-based experiments employing inertial isolation systems with optical readout.