Wavefront control testbed experimental results

Burns, Laura A.; Basinger, Scott A.; Campion, Scott D.; Faust, J.; Feinberg, Lee; Green, Joseph Jacob; Hayden, William L.; Lowman, Andrew E.; Ohara, Catherine M.; Petrone, Peter; Redding, David C.; Zukowski, Barbara

doi:10.1117/12.551794

Cited by 2 publications

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“…The modulation transfer function (MTF) is the mode of OTF, which describes the transmission characteristics of the contrast of each frequency component of the imaging system. The alignment error of the segmented primary mirror will result in the decrease of PSF energy and dispersion of light spot in the spatial domain [17], [18], the corresponding integral area of MTF will also decrease in the frequency domain. Therefore, the influence of alignment error on system imaging performance perhaps can be reflected by PSF and MTF in spatial and frequency domains, respectively.…”

Section: Theoretical Basismentioning

confidence: 99%

An Image-based alignment errors correction method for segmented Fresnel primary mirror

et al. 2020

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The alignment errors correction of segmented Fresnel primary mirror in multiple imaging scenes is simulated. Based on the linear relationship between five kinds of alignment errors and modulation transfer function metric or image frequency domain metric, an iterative correction method is introduced to compensate the alignment errors of segmented Fresnel lens at five degrees of freedom. The correction capability under point target imaging and the effect of alignment error correction under extended target imaging are studied. The simulation results show that the proposed correction scheme can effectively correct the alignment error when the rms value of segmented Fresnel primary mirror is less than 0.7λ. This method does not need to add any additional devices to the telescope, but optimizes directly based on the images, and is independent of the spatial structure of the imaging target. It may be suitable for fine phasing correction of segmented membrane diffractive optical telescope in orbit.

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Section: Theoretical Basismentioning

confidence: 99%

An Image-based alignment errors correction method for segmented Fresnel primary mirror

et al. 2020

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“…Simulations, analysis and even laboratory tests have already been carried out to demonstrate the success of DFS and DHS for the JWST (Wirth 2000; Smith et al. 2003;Shi et al 2002;Burns et al 2004). It is different from the mature and widely used Shack-Hartmann wavefront sensor and curvature wavefront sensor with edge sensors for calibration of relative pistons.…”

Section: Introductionmentioning

confidence: 99%

Preliminary study of a dispersed fringe type sensing system

Zhang

Liu

Wang

et al. 2009

Res. Astron. Astrophys.

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Telescopes with large aspherical primary mirrors collect more light and are therefore sought after by astronomers. Instead of using a single large one-piece mirror, smaller segments can be assembled into a useable telescopic primary. Because the segments must fit together to create the effect of a single mirror, segmented optics present unique challenges to the fabrication and testing that are absent in monolithic optics. A dispersed fringe sensor (DFS) using a broadband point source is an efficient method for cophasing and is also highly automated and robust. Unlike the widely adopted Shack-Hartmann Wavefront sensor and curvature wavefront sensor with edge sensors for calibration of relative pistons, DFS can estimate the piston between segments by only using the spectrum formed by the transmissive grating's dispersion, and therefore can replace the edge sensors, which are difficult to calibrate. We introduce the theory of the DFS and Dispersed Hartmann Sensor (DHS) for further utilization of the coarse phasing method of DFS. According to the theory, we bring out the preliminary system design of the cophasing experimental system based on DFS and DHS which is now established in our institute. Finally, a summary is reached.

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Wavefront control testbed experimental results

Cited by 2 publications

References 0 publications

An Image-based alignment errors correction method for segmented Fresnel primary mirror

An Image-based alignment errors correction method for segmented Fresnel primary mirror

Preliminary study of a dispersed fringe type sensing system

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