The aggregate behavior of branch points: verification in wave optical simulation II

Oesch, Denis W.; Tewksbury-Christle, Carolyn M.; Sanchez, Darryl J.; Kelly, Patrick R.

doi:10.1117/12.928502

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…5 After which, researchers began investigating 1) the impact that branch-point formation has on laser-propagation systems [6][7][8][9][10][11][12][13][14] and 2) the physical insight that can be gleaned about the atmospheric turbulence environment through which the beam propagated. 3,4,[15][16][17][18][19][20][21][22][23][24][25][26] These motivations make it advantageous to develop approaches which easily and robustly identify branch points from optical-turbulence measurements.…”

Section: Introductionmentioning

confidence: 99%

Branch-point detection using a Shack-Hartmann wavefront sensor

Kalensky,

Oesch,

Bukowski

et al. 2023

Unconventional Imaging, Sensing, and Adaptive Optics 2023

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In this paper, two methods for identifying branch points from Shack–Hartmann wavefront sensor (SHWFS) measurements were studied; the circulation of phase gradients approach and the beam-spread approach. These approaches were tested using a simple optical-vortex model, wave-optics simulations, and with experimental data. It was found that these two approaches are synergistic regarding their abilities to detect branch points. Specifically, the beam-spread approach works best when the branch point is located towards the center of the SHWFS’s lenslet pupil, while the circulation of phase gradients approach works best when the branch point is located towards the edge of the SHWFS’s lenslet pupil. These behavior were observed studying the simple optical-vortex model; however, they were further corroborated with the wave-optics and experimental results. The developments presented within support researchers looking to study high scintillation optical-turbulence environments as well as will inform efforts looking to develop branch-point tolerant reconstruction algorithms.

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Section: Introductionmentioning

confidence: 99%

Branch-point detection using a Shack-Hartmann wavefront sensor

Kalensky,

Oesch,

Bukowski

et al. 2023

Unconventional Imaging, Sensing, and Adaptive Optics 2023

View full text Add to dashboard Cite

show abstract

“…The work of Fried and Vaughn first investigated the problem of branch-point formation caused by propagation through distributed-volume turbulence, 5 after which researchers began investigating (1) the impact that branch-point formation has on laser-propagation systems 6 – 14 and (2) the physical insight that can be gleaned about the atmospheric turbulence environment through which the beam propagated 3 , 4 , 15 – 26 These motivations make it advantageous to develop approaches that easily and robustly identify branch points from optical-turbulence measurements.…”

Section: Introductionmentioning

confidence: 99%

“…propagated. 3,4,[15][16][17][18][19][20][21][22][23][24][25][26] These motivations make it advantageous to develop approaches that easily and robustly identify branch points from optical-turbulence measurements.…”

mentioning

confidence: 99%

Comparison of branch-point detection approaches using a Shack–Hartmann wavefront sensor

Kalensky,

Oesch,

Bukowski

et al. 2023

Opt. Eng.

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Two methods for identifying branch points from Shack-Hartmann wavefront sensor (SHWFS) measurements were studied: the circulation of phase gradients approach and the beam-spread approach. These approaches were tested using a simple optical-vortex model, with wave-optics simulations, and with experimental data. It was found that these two approaches are synergistic regarding their abilities to detect branch points. Specifically, the beam-spread approach works best when the branch point is located toward the center of the SHWFS's lenslet pupil, whereas the circulation of phase gradients approach works best when the branch point is located toward the edge of the SHWFS's lenslet pupil. These behaviors were observed studying the simple optical-vortex model; however, they were further corroborated with the wave-optics and experimental results. The developments presented support researchers studying high scintillation optical-turbulence environments and inform efforts in developing branch-point tolerant reconstruction algorithms.

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Branch-point compensation in extended-beacon adaptive optics

Kalensky,

Burrell,

Spencer

et al. 2024

Unconventional Imaging, Sensing, and Adaptive Optics 2024

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In this paper, we use wave-optics simulations to explore laser propagation system performance. We accomplish this by creating a trade space where we vary turbulence conditions as well as beacon size from a point-source beacon to an extended-source beacon with an object Fresnel number, N obj , of 20. We explore performance when we employ no compensation, perfect phase compensation, and perfect full-phase compensation. The results of this trade space allow us to arrive at three main conclusions. First, if we have either a point-source beacon or a very small extended-source beacon and turbulence is strong, we get a significant improvement in performance using full-phase compensation compared to least-squares compensation and no compensation. If turbulence is weak, we see similar performance with least-squares and full-phase compensation, however, both are significantly improved over the no compensation case. Second, in strong turbulence conditions, there will be a very large number of turbulence-induced branch points. If left uncompensated, these turbulence-induced branch points will result in a major reduction in performance. Lastly, when the extended-source beacon is large, the associated roughsurface-scattering-induced phase aberrations will corrupt the compensation to the point where the drawbacks of compensating for surface-roughness-induced aberrations significantly outweigh the benefits of compensating for turbulence-induced aberrations. These results (1) inform researchers looking to conduct extended-source-beacon adaptive optics and (2) motivate research to explore methods for speckle mitigation in adaptive-optics systems.

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The aggregate behavior of branch points: verification in wave optical simulation II

Cited by 4 publications

References 9 publications

Branch-point detection using a Shack-Hartmann wavefront sensor

Branch-point detection using a Shack-Hartmann wavefront sensor

Comparison of branch-point detection approaches using a Shack–Hartmann wavefront sensor

Branch-point compensation in extended-beacon adaptive optics

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