A Compact Cold-Atom Interferometer with a High Data-Rate Grating Magneto-Optical Trap and a Photonic-Integrated-Circuit-Compatible Laser System

TL;DR

This paper presents a miniaturized cold-atom interferometer with a high data-rate, utilizing a compact vacuum package, a microfabricated grating MOT, and a photonic-integrated laser system, achieving fast measurements suitable for deployable inertial sensing.

Contribution

The development of a compact, integrated cold-atom interferometer system with a novel laser architecture and microfabricated components for high-rate inertial measurements.

Findings

Achieved 15 μK temperature in sub-Doppler cooling.

Operated at a 20 Hz data rate with the GMOT.

Demonstrated a gravimeter with Δg/g = 2.0e-6 at 10 Hz.

Abstract

The extreme miniaturization of a cold-atom interferometer accelerometer requires the development of novel technologies and architectures for the interferometer subsystems. Here we describe several component technologies and a laser system architecture to enable a path to such miniaturization. We developed a custom, compact titanium vacuum package containing a microfabricated grating chip for a tetrahedral grating magneto-optical trap (GMOT) using a single cooling beam. In addition, we designed a multi-channel photonic-integrated-circuit-compatible laser system implemented with a single seed laser and single sideband modulators in a time-multiplexed manner, reducing the number of optical channels connected to the sensor head. In a compact sensor head containing the vacuum package, sub-Doppler cooling in the GMOT produces 15 uK temperatures, and the GMOT can operate at a 20 Hz data rate. We validated the atomic coherence with Ramsey interferometry using microwave spectroscopy, then demonstrated a light-pulse atom interferometer in a gravimeter configuration for a 10 Hz measurement data rate and T = 0 - 4.5 ms interrogation time, resulting in $\Delta$ g / g = 2.0e-6. This work represents a significant step towards deployable cold-atom inertial sensors under large amplitude motional dynamics.