Share Email Print
cover

Proceedings Paper

High-QE fast-readout wavefront sensor with analog phase reconstruction
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

The contradiction inherent in high temporal bandwidth adaptive optics wavefront sensing at low-light-levels (LLL) has driven many researchers to consider the use of high bandwidth high quantum efficiency (QE) CCD cameras with the lowest possible readout noise levels. Unfortunately, the performance of these relatively expensive and low production volume devices in the photon counting regime is inevitably limited by readout noise, no matter how arbitrarily close to zero that specification may be reduced. Our alternative approach is to optically couple a new and relatively inexpensive Ultra Blue Gen III image intensifier to an also relatively inexpensive high bandwidth CCD camera with only moderate QE and high rad noise. The result is a high bandwidth broad spectral response image intensifier with a gain of 55,000 at 560 nm. Use of an appropriately selected lenslet array together with coupling optics generates 16 X 16 Shack-Hartmann type subapertures on the image intensifier photocathode, which is imaged onto the fast CCD camera. An integral A/D converter in the camera sends the image data pixel by pixel to a computer data acquisition system for analysis, storage and display. Timing signals are used to decode which pixel is being rad out and the wavefront is calculated in an analog fashion using a least square fit to both x and y tilt data for all wavefront sensor subapertures. Finally, we present system level performance comparisons of these new concept wavefront sensors versus the more standard low noise CCD camera based designs in the low-light-level limit.

Paper Details

Date Published: 11 September 1998
PDF: 11 pages
Proc. SPIE 3353, Adaptive Optical System Technologies, (11 September 1998); doi: 10.1117/12.321705
Show Author Affiliations
Jeffrey T. Baker, Boeing North American (United States)
Gary C. Loos, Air Force Research Lab. (United States)
Sergio R. Restaino, Air Force Research Lab. (United States)
Isabelle Percheron, Boeing North American (Netherlands)
Lyle G. Finkner, Boeing North American (United States)


Published in SPIE Proceedings Vol. 3353:
Adaptive Optical System Technologies
Domenico Bonaccini; Robert K. Tyson, Editor(s)

© SPIE. Terms of Use
Back to Top