# Compact multi-fringe interferometry with sub-picometer precision

## TL;DR

This paper introduces a compact, single-component multi-fringe interferometer capable of sub-picometer precision, suitable for high-precision applications like satellite geodesy and gravity experiments.

## Contribution

It presents a miniaturized interferometer design that achieves high tilt and displacement measurement precision, demonstrating its potential for space and ground-based high-precision sensing.

## Key findings

- Achieved tilt measurement precision of less than 20 nrad/√Hz.
- Achieved displacement measurement precision of less than 1 pm/√Hz.
- Demonstrated effective performance below 1 Hz frequency range.

## Abstract

Deep frequency modulation interferometry combines optical minimalism with multi-fringe readout. Precision however is key for applications such as optical gradiometers for satellite geodesy or as dimensional sensor for ground-based gravity experiments. We present a single-component interferometer smaller than a cubic inch. Two of these are compared to each other to demonstrate tilt and displacement measurements with a precision of less than $20\,\mathrm{nrad}/\sqrt{\mathrm{Hz}}$ and $1\,\mathrm{pm}/\sqrt{\mathrm{Hz}}$ at frequencies below $1\,\mathrm{Hz}$.