Binary adaptive optics: atmospheric wave-front correction with a half-wave phase shifter

Love, Gordon D.; Andrews, N.; Birch, Philip; Buscher, David F.; Doel, P.; Dunlop, Colin; Major, J. V.; Myers, R; Purvis, Alan; Sharples, R. M.; Vick, Andrew; Zadrozny, Andrew; Restaino, Sergio R.; Glindemann, Andreas

doi:10.1364/ao.34.006058

Cited by 29 publications

(14 citation statements)

References 9 publications

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“…Although a mask could be devised to yield the asymptotic MTF for specific spatial frequencies, it is unlikely that masks exist that approach the limit at all spatial frequencies simultaneously. However, significant image contrast across all spatial frequencies is obtained for masks that selectively block destructively interfering parts of the aperture, and such a mask can be considered to be the amplitude mask equivalent of the phase mask proposed by Love et al [9,10]. Here we derive an analytical expression for the MTF when masking arbitrarily large aberrations, which can be seen to be in agreement with the Strehl ratio found for the phase mask in [9].…”

Section: Introductionsupporting

confidence: 77%

“…However, significant image contrast across all spatial frequencies is obtained for masks that selectively block destructively interfering parts of the aperture, and such a mask can be considered to be the amplitude mask equivalent of the phase mask proposed by Love et al [9,10]. Here we derive an analytical expression for the MTF when masking arbitrarily large aberrations, which can be seen to be in agreement with the Strehl ratio found for the phase mask in [9]. Furthermore, we show that for aberrations as large as 3.5 waves of root-mean-square optical path difference, part of the MTF can be increased beyond the asymptotic limit by optimization of three additional free parameters of the mask.…”

Section: Introductionmentioning

confidence: 99%

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Correction of optical phase aberrations using binary-amplitude modulation

Vettenburg

Harvey

2011

J. Opt. Soc. Am. A

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We show that phase aberrations in an imaging system can be mitigated using binary-amplitude masks that reduce destructive interference in the image spatial frequency domain. Appropriately designed masks increase the magnitude of the optical transfer function and prevent nulls. This offers a low-cost, transmission-mode alternative to phase correction as used in active and adaptive optics, without a restriction on the waveband of operation.

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Section: Introductionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Correction of optical phase aberrations using binary-amplitude modulation

Vettenburg

Harvey

2011

J. Opt. Soc. Am. A

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“…In the first approach, significant image contrast across all spatial frequencies is obtained by employing a low-dimensional mask optimization that involves selective blocking to reduce destructive interference from parts of the aperture 7 , we call these contour masks and they can be considered to be the amplitude-mask equivalent of the phase masks proposed by Love et al 8,9 . An analytical expression for the upper limit of the modulation transfer function (MTF) of an imaging system with large aberrations and a contour mask is also reported.…”

Section: Introductionmentioning

confidence: 99%

Control of optical aberrations with coded apertures

Harvey¹,

Muyo²,

Vettenburg³

2011

SPIE Proceedings

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We report the design of binary-amplitude masks that in conjunction with digital restoration enable mitigation of optical aberrations. Essentially, the design process aims to maintain high modulation-transfer functions by reducing destructive interference of optical-transfer-function phasors. Two optimization techniques are described: so-called contour masks and the use of multiple pixelated masks. In general the resultant modulation-transfer function is 20% of a diffractionlimited imaging system and due to the absence of nulls recorded images can be restored to a high-contrast diffractionlimited image. Example applications are presented for correcting ocular aberrations and for conformal imaging.

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“…[1] and [2] for a good overview of the field). The use of spatial light modulators (SLMs) (or their early variants) have previously been suggested and used for the production of Zernike modes, adaptive optics and turbulence generation [3][4][5][6][7] . Most of the approaches attempting to demonstrate turbulence have concentrated on Kolmogorov turbulence, and have made use of the SLM as the turbulence screen.…”

Section: Introductionmentioning

confidence: 99%

Laser beam shaping limitations for laboratory simulation of turbulence using a phase-only spatial light modulator

et al. 2007

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Recent approaches to demonstrating adaptive optics and atmospheric turbulence have made use of spatial light modulators (SLMs) as the active phase element. However, there are limitations in using SLMs as an accurate method of simulating turbulence phase screens. In this work we investigate the limitation of laser beam shaping with a phase-only spatial light modulator for the simulation of dynamic and pseudo-random turbulence in the laboratory. We find that there are regimes where there are not sufficient pixels to resolve the phase. At the higher end of this range, at strong turbulence levels, the zonal regions are tightly packed. This leads to two simultaneous effects: a phase screen with low efficiency in some regions, and a modified turbulence structure due to the shifting of the zone peaks. These amplitude and phase distortions have a deleterious effect on the accurate simulation of the turbulence. At the lower end of the range, at weak turbulence, the phase change is too small to describe with sufficient grey scale levels, since the full 256 levels are associated with a full 2π phase shift. Further limitations include the frame rate of SLM for time-evolving turbulence. We show experimental results demonstrating these limitations, and discuss the impact this has on simulating turbulence with SLMs.

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Binary adaptive optics: atmospheric wave-front correction with a half-wave phase shifter

Cited by 29 publications

References 9 publications

Correction of optical phase aberrations using binary-amplitude modulation

Correction of optical phase aberrations using binary-amplitude modulation

Control of optical aberrations with coded apertures

Laser beam shaping limitations for laboratory simulation of turbulence using a phase-only spatial light modulator

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