Paper
22 July 2010 Laboratory demonstration of an anti-halo reconstructor for closed-loop adaptive halo suppression
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Abstract
In order to suppress the halo and any residual speckles over a region of interest, we find an anti-halo reconstructor which gives the required changes to a deformable mirror (DM) at the pupil plane. The reconstructor is built from a training set consisting of measurements of the complex halo influence functions for a spanning set of Fourier modes applied to the DM. The reconstructor is then found by multiplying the applied DM actuator values by the singular value decomposition (SVD) pseudo-inverse of the measured complex halo influence functions. Using a single fully illuminated 12×12 actuator DM at the pupil plane, halo suppression for complex pupils out to the control radius of 6 λ/D can be provided. In practice, a coronagraph is unlikely to achieve high performance without adaptive tuning. We use a coronagraphic focal plane interferometer [1], where the focal plane mask diverts the bright starlight for use as an interferometric reference beam to measure the residual complex halo. The result of the reconstructor acting on the complex halo measurements allowed us to implement a closed loop halo-suppression servo. We discuss the laboratory implementation and experience with this technique.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Esen Salçın and Johanan L. Codona "Laboratory demonstration of an anti-halo reconstructor for closed-loop adaptive halo suppression", Proc. SPIE 7736, Adaptive Optics Systems II, 77362S (22 July 2010); https://doi.org/10.1117/12.857825
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KEYWORDS
Coronagraphy

Actuators

Speckle

Phase measurement

Calibration

Adaptive optics

Servomechanisms

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