MOAO test bench in Tohoku University

Abstract

We are conducting AO development activities in Tohoku university targeting Multi-Object Adaptive Optics (MOAO) system for the next generation ground-based large telescopes. In order to evaluate the accuracy of the tomographic estimation, which is a key of an MOAO system, we assembled a test optical bench to simulate an MOAO system in our optical lab. The system consists with 1) four light sources with single-mode fibers simulating three guide stars and one target object, 2) multiple phase plates simulating atmospheric turbulence structure, and 3) 4 Shack-Hartmann wavefront sensors. Wavefront data from the sensors are reduced with the tomographic algorithm. The evaluation of the accuracy of the tomographic wavefront reconstruction is underway. Additionally, evaluation of an open-loop control of an AO system is underway using an independent module. Once the accuracy of the open-loop control is established, the module will be installed in the tomography test bench and the entire system will be evaluated as an MOAO system. In parallel, we are conducting a development of a large stroke (20μm) Micro Electro Mechanical Systems (MEMS) deformable mirror with large number of elements (<3000). Current status of the development is described.