Gemini Preprint #69

A Wave Optics Propagation Code for Multi-Conjugate Adaptive Optics

B. L. Ellerbroek
Gemini Observatory Northern Operations Center, 670 N. A'ohoku Place, Hilo HI 96720


We describe the purpose and sample results of a wave optics propagation simulation developed to study multi-conjugate adaptive optics for 4-10 m class telescopes. This code was developed to assess the impact of diffraction effects and a variety of implementation error sources upon the performance of the Gemini-South MCAO system. These effects include: Hartmann sensing with extended and elongated laser guide stars, optical propagation effects through the optics and atmosphere, laser guide star projection through the atmosphere, deformable mirror and wave front sensor misregistration, and calibration for non-common path errors. The code may be run in either a wave optics or geometric propagation mode to allow the code to be anchored against linear analytical models and to explicitly evaluate the impact of diffraction effects. The code is written in MATLAB, and complete simulations of the Gemini-South MCAO design (including 3 deformable mirrors with 769 actuators, 5 LGS WFS with 1020 subapertures, 3 tip/tilt NGS WFS, and 50 meter phase screens with 1/32nd meter resolution) are possible using a Pentium III but require 1 to 6 days. Sample results are presented in the Gemini-South MCAO system.

To appear in the proceedings of "Beyond Conventional Adaptive Optics".

Download the PDF file.

Ruth A. Kneale / / July 12, 2001