Apollon Real-Time Adaptive Optics (ARTAO) -- Astronomy-Inspired Wavefront Stabilization in Ultraintense Lasers

TL;DR

This paper presents a real-time adaptive optics system for high-energy lasers, inspired by astronomy, using a GPU controller and spectral separation to improve wavefront stabilization during experiments.

Contribution

It introduces a novel real-time adaptive optics system for ultraintense lasers, leveraging astronomical techniques and spectral separation for improved wavefront correction.

Findings

Successful initial stability tests of the AO system.

Effective aberration correction demonstrated in laboratory conditions.

Identified challenges for integration into operational laser environment.

Abstract

Traditional wavefront control in high-energy, high-intensity laser systems usually lacks real-time capability, failing to address dynamic aberrations. This limits experimental accuracy due to shot-to-shot fluctuations and necessitates long cool-down phases to mitigate thermal effects, particularly as higher repetition rates become essential, e.g. in Inertial Fusion research. This paper details the development and implementation of a real-time capable adaptive optics system at the Apollon laser facility. Inspired by astronomical adaptive optics, the system uses a fiber-coupled 905 nm laser diode as a pilot beam that allows for spectral separation, bypassing the constraints of pulsed lasers. A GPU-based controller, built on the open-source CACAO framework, manages a loop comprising a bimorph deformable mirror and high-speed Shack-Hartmann sensor. Initial tests showed excellent stability and effective aberration correction. However, integration into the Apollon laser revealed critical challenges unique to the laser environment that must be resolved to ensure safe operation with amplified shots.