The GPU-based High-order adaptive OpticS Testbench

TL;DR

GHOST is a GPU-based adaptive optics testbench designed to evaluate advanced control methods like machine learning for next-generation telescopes, combining simulation and real-time correction with high flexibility.

Contribution

Introduces GHOST, a novel 2-stage adaptive optics testbench integrating simulation and real hardware for testing new control algorithms in extreme adaptive optics.

Findings

Successful integration of simulation and hardware correction stages

Capability to test machine learning and predictive control methods

Flexible platform for various adaptive optics research

Abstract

The GPU-based High-order adaptive OpticS Testbench (GHOST) at the European Southern Observatory (ESO) is a new 2-stage extreme adaptive optics (XAO) testbench at ESO. The GHOST is designed to investigate and evaluate new control methods (machine learning, predictive control) for XAO which will be required for instruments such as the Planetary Camera and Spectrograph of ESOs Extremely Large Telescope. The first stage corrections are performed in simulation, with the residual wavefront error at each iteration saved. The residual wavefront errors from the first stage are then injected into the GHOST using a spatial light modulator. The second stage correction is made with a Boston Michromachines Corporation 492 actuator deformable mirror and a pyramid wavefront sensor. The flexibility of the bench also opens it up to other applications, one such application is investigating the flip-flop modulation method for the pyramid wavefront sensor.