Digital Wavefront Sensor For Astronomical Image Compensation

Allen, Jeffrey; Jankevics, Andy; Wormell, Dean; Schmutz, L.

doi:10.1117/12.939713

Cited by 10 publications

(2 citation statements)

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“…For real time adaptive optics systems where the wavefront must be reconstructed rapidly, it can save precious computer time. For example, a four-tier system can estimate a fourth order (x and y) wavefront error with 21 operations, compared (3) to 4000-250,000 using an efficient Shack-Hartmann wavefront reconstruction. Furthermore, the information can be carried through the control system in the form of a few coefficients, rather than a table of random data.…”

Section: Continuous Wavefront Error Measurementmentioning

confidence: 99%

<title>Multitiered wavefront sensor using binary optics</title>

Neal¹,

Warren²,

Gruetzner³

et al. 1994

Adaptive Optics in Astronomy

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Wavefront sensors have been used to make measurements in fluid-dynamics and for closed loop control of adaptive optics. In most common Shack-Hartmann wavefront sensors, the light is broken up into series of rectangular or hexagonal apertures that divide the light into a series of focal spots. The position of these focal spots is used to determine the wavefront slopes over each subaperture. Using binary optics technology, we have developed a hierarchical or fractal wavefront sensor that divides the subapertures up on a more optimal fashion. We have demonstrated this concept for up to four tiers and developed the wavefront reconstruction methods for both segmented adaptive optics and con tinous wavefront measurement.

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Section: Continuous Wavefront Error Measurementmentioning

confidence: 99%

<title>Multitiered wavefront sensor using binary optics</title>

Neal¹,

Warren²,

Gruetzner³

et al. 1994

Adaptive Optics in Astronomy

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“…Frequently used methods for phase measurement include phase-shifting interferometry [2]- [6], the use of a Hartmann sensor [7]- [10], and lateral shearing interferometry [11].…”

Section: Introductionmentioning

confidence: 99%

Basic module for an integrated optical phase difference measurement and correction system

Golubovic

Donnelly

Wang

et al. 1995

IEEE Photon. Technol. Lett.

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A basic module for an integrated optical phase difference measurement and correction system was developed and fabricated in the GaAs-AlGaAs material system. The implemented device made it possible to measure the relative phase difference between two waveguides using a small fraction of the power (<10%) for diagnostic purposes. This proof-of-concept device incorporated waveguides, waveguide couplers and Y-junctions, phase modulators, and photodetectors on the same substrate. This thesis describes the design, fabrication and operation of the implemented device. Waveguide phase modulators with Vx=5.0V for =-0.865gm were fabricated. Selective Be ion implantation and rapid thermal annealing was used to form the p+-n--n + modulator structure. The phase was modulated via the linear electrooptic effect in the reverse-biased p+-n--n + structure. A Y-junction interferometer was used to obtain the relative phase difference between the two waveguides. Integrated MSM photodetectors, 17x69gm in size, with TIR mirror coupling were used for signal detection. Both, the interferometer and detector were fabricated and operated between two, 30gtm separated waveguides. A phase dither detection system made it possible to determine the relative phase between two waveguides largely independent of the power ratio between the individual guides.

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