The use of a high-order MEMS deformable mirror in the Gemini Planet Imager

Lisa A. Poyneer, Brian Bauman, Steven Cornelissen, Joshua Isaacs, Steven Jones, Bruce A. Macintosh, David W. Palmer, Scot S. Olivier, Thomas G. Bifano, Joel A. Kubby
2011 MEMS Adaptive Optics V  
We briefly review the development history of the Gemini Planet Imager's 4K Boston Micromachines MEMS deformable mirror. We discuss essential calibration steps and algorithms to control the MEMS with nanometer precision, including voltage-phase calibration and influence function characterization. We discuss the integration of the MEMS into GPI's Adaptive Optics system at Lawrence Livermore and present experimental results of 1.5 kHz closed-loop control. We detail mitigation strategies in the
more » ... rategies in the coronagraph to reduce the impact of abnormal actuators on final image contrast. Send correspondence to Lisa Poyneer:, 1 925 423 3360 Despite the large increase in stroke that occurred during the GPI MEMS development process, a single MEMS DM does not have adequate stroke to fully correct typical atmospheric turbulence. Under Kolmogorov theory, low spatial frequency phase errors have the largest amplitude. A low-order, high-stroke DM can be used as a Woofer to correct the low spatial frequencies, leaving the higher frequency, lower amplitude errors for the MEMS. Lavingne and Véran 13 provide a detailed discussion of the GPI Woofer parameter specification process and the control algorithms necessary to split the phase between the two mirrors.
doi:10.1117/12.876496 fatcat:vkokwt437vfpdnupp7wa6pjfvm