# Precise and robust optical beam steering for space optical instrumentation

## TL;DR

This paper introduces a highly precise and stable optical beam steering method that significantly improves fiber coupling efficiency and simplifies design, suitable for space-based quantum experiments.

## Contribution

The paper presents a novel beam steering technique offering sub-5 microradian precision, enhanced stability, and simplified fiber coupler design for space optical instrumentation.

## Key findings

- Achieved better than 5 μrad and 5 μm precision.
- Demonstrated over 89.8% fiber coupling efficiency.
- Maintained stability over temperature variations.

## Abstract

This approach permits much finer adjustments of the beam direction and position when compared to other beam steering techniques of the same mechanical precision. This results in a much increased precision, accuracy and mechanical stability. A precision of better than 5 {\mu}rad and 5 {\mu}m is demonstrated, resulting in a resolution in coupling efficiency of 0.1%. Together with the added flexibility of an additional beam steering element, this allows a great simplification of the design of the fiber coupler, which normally is the most complex and sensitive element on an optical fiber breadboard. We demonstrate a fiber to fiber coupling efficiency of more than 89.8%, with a stability of 0.2% in a stable temperature environment and 2% fluctuations over a temperature range from 10C to 40C over a measurement time of 14 hours. Furthermore, we do not observe any non-reversible change in the coupling efficiency after performing a series of tests over large temperature variations. This technique finds direct application in proposed missions for quantum experiments in space, e.g.where laser beams are used to cool and manipulate atomic clouds.