The aggregate behavior of branch points: the use of branch point pairing to generate a hidden phase for closed-loop AO

Carolyn M. Tewksbury-Christle; Denis W. Oesch; Darryl J. Sanchez; Patrick R. Kelly

doi:10.1117/12.827778

11 August 2009 The aggregate behavior of branch points: the use of branch point pairing to generate a hidden phase for closed-loop AO

Carolyn M. Tewksbury-Christle, Denis W. Oesch, Darryl J. Sanchez, Patrick R. Kelly

Author Affiliations +

Proceedings Volume 7466, Advanced Wavefront Control: Methods, Devices, and Applications VII; 746607 (2009) https://doi.org/10.1117/12.827778
Event: SPIE Optical Engineering + Applications, 2009, San Diego, California, United States

Abstract

Recent research has shown that branch points, as they appear in astronomical applications, have a rich collective behavior, showing, in particular, that branch point pairs have a well-defined, non-stoichastic velocity, and that once a branch point pairs location is measured, it can be tracked in open-loop adaptive optics operation. The research presented here uses this new information as a priori knowledge in closed-loop AO. Specifically, an algorithm was developed that measures branch point location and velocity at time t_k and then uses this to estimate the phase contribution at time t_k+n, giving it an effective memory of where branch points appear and allowing it to determine more accurately between real branch points and noise. The output of the new algorithm is used as a second input to the DM control law. Results of initial closed-loop AO tests will be presented.

Citation Download Citation

Carolyn M. Tewksbury-Christle, Denis W. Oesch, Darryl J. Sanchez, and Patrick R. Kelly "The aggregate behavior of branch points: the use of branch point pairing to generate a hidden phase for closed-loop AO", Proc. SPIE 7466, Advanced Wavefront Control: Methods, Devices, and Applications VII, 746607 (11 August 2009); https://doi.org/10.1117/12.827778

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