Interferometric sensing of a commercial geophone

TL;DR

This paper introduces an interferometric readout for a commercial geophone, significantly enhancing low-frequency sensitivity and demonstrating potential for improved vibration isolation in precision systems.

Contribution

A modified commercial geophone with interferometric readout is developed, achieving much lower resolution at low frequencies and enabling better vibration control in sensitive applications.

Findings

Resolution improved by 60 times at low frequencies.

Sensor can reduce residual vibration by a factor of 70 at 0.1 Hz.

Potential application in advanced vibration isolation systems.

Abstract

We present a modified commercial L-4C geophone with interferometric readout that demonstrated a resolution 60 times lower than the included coil-magnet readout at low frequencies. The intended application for the modified sensor is in vibration isolation platforms that require improved performance at frequencies lower than 1 Hz. A controls and noise-model of an Advanced LIGO 'HAM-ISI' vibration isolation system was developed, and it shows that our sensor can reduce the residual vibration by a factor of 70 at 0.1 Hz