Abstract
A new design for a wavefront sensor suitable for low-order low-light correction is shown. The hybrid modal sensor, the Nine Element (NE) sensor, is compared with a curvature sensor and quadcell under single aperture applications. The design of the NE sensor allows the use of readily-available array detectors. We discuss the optimization of the design to maximize its performance with respect
to the number of Zernike polynomials to detect and optical parameters, using a simulated annealing technique. Numerical simulations show the good SNR response low-light levels, and indicate a reduction in wavefront variance from 6.41 rad
to 2.01 rad
. The sensitivity to tip/tilt errors
is demonstrated to be comparable to a quadcell. Successful closed feedback loop operation results in corrected Strehl ratios of over 0.5. Improvements and future work is discussed.