Compact and robust design of the optical system for cold atom interferometer in space

TL;DR

This paper presents a compact, robust optical system design for space-based cold atom interferometers, demonstrating stability and functionality in space conditions, suitable for future space quantum sensors.

Contribution

The paper introduces a novel, integrated optical system design optimized for space applications, ensuring robustness, compactness, and dual-species atom interferometry capability.

Findings

Optical system size: 250mm x 240mm x 104mm, weight: 5.2kg.

Laser power stability: less than 15% variation from ground to space.

Long-term laser power fluctuations: less than 2.5% over months in space.

Abstract

The optical system is a complex and precise subsystem for the atom interferometer (AI), especially for those used in field or space applications. Here, we introduce the design of the optical system of the China Space Station atom interferometer (CSSAI). The scheme is optimized to reduce the complexity while maintaining the capability to achieve the dual-species AI. It features a fused silica optical bench with bonding technology, ensuring compactness and smaller thermal deformation. Spatial structures are designed to isolate the vibration and transfer the heat. After assembling, the optical system has a size of 250 mm * 240 mm * 104 mm and weighs 5.2 kg. After installing in the CSSAI, it passed the thermal and mechanical tests and then launched to the China Space Station (CSS). The output laser power changes are less than 15% from ground to space, and its long-term fluctuations are less than 2.5% for months in space. Cold atom preparation and interference are also realized in space. This optical system is extremely integrated and robust, which provides a foundation for the design of future cold atom payloads in space.