Enabling laboratory demonstrations of multi-object adaptive optics with linearity calibrations

Ammons, S. Mark; Laag, Edward A.; Kupke, Renate; Gavel, Donald T.; Max, C. E.

doi:10.1117/12.735085

Cited by 7 publications

(7 citation statements)

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“…However, because this bench uses bright guide stars, the measurement error is largely not affected. The elongation actually decreases WFS systematic error due to WFS nonlinearity effects (Ammons et al 2007). As the effect of elongation is slight, we do not perform this step for the experiments presented in this paper.…”

Section: Lgs Elongationmentioning

confidence: 99%

“…This effect is exacerbated in systems with small Hartmann spot sizes, especially less than one pixel in FWHM. The various difficulties associated with open-loop wavefront sensing are described in more detail in Ammons et al (2007).…”

Section: Open-loop Performance Of Wavefront Sensorsmentioning

confidence: 99%

“…Total intensity variation must be low for all layers, as the Hartmann sensor is sensitive to intensity dropouts. Power spectra of phase for the various plates used are shown in previous publications (Ammons et al 2007).…”

Section: Atmospheric Phase Platesmentioning

confidence: 99%

“…The control algorithms for this testbench are discussed in more detail in prior publications (Ammons et al 2006(Ammons et al , 2007Laag et al 2008) and here summarized. No part of the reconstruction or control is matrix-based.…”

Section: Software and Controlmentioning

confidence: 99%

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Integrated Laboratory Demonstrations of Multi-Object Adaptive Optics on a Simulated 10 Meter Telescope at Visible Wavelengths

Ammons¹,

Johnson²,

Laag³

et al. 2010

PUBL ASTRON SOC PAC

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One important frontier for astronomical adaptive optics (AO) involves methods such as Multi-Object AO and Multi-Conjugate AO that have the potential to give a significantly larger field of view than conventional AO techniques. A second key emphasis over the next decade will be to push astronomical AO to visible wavelengths. We have conducted the first laboratory simulations of wide-field, laser guide star adaptive optics at visible wavelengths on a 10-meter-class telescope. These experiments, utilizing the UCO/Lick Observatory's Multi-Object / Laser Tomography Adaptive Optics (MOAO/LTAO) testbed, demonstrate new techniques in wavefront sensing and control that are crucial to future on-sky MOAO systems. We (1) test and confirm the feasibility of highly accurate atmospheric tomography with laser guide stars, (2) demonstrate key innovations allowing open-loop operation of Shack-Hartmann wavefront sensors (with errors of ∼ 30 nm) as will be needed for MOAO, and (3) build a complete error budget model describing system performance. The AO system maintains a performance of 32.4% Strehl on-axis, with 24.5% and 22.6% at 10. ′′ and 15. ′′ , respectively, at a science wavelength of 710 nm (R-band) over the equivalent of 0.8 seconds of simulation. The mean ensquared energy on-axis in a 50 milliarcsecond spaxel is 46%. The off-axis Strehls are obtained at radial separations 2-3 times the isoplanatic angle of the atmosphere at 710 nm. The MOAO-corrected field of view is ∼ 25 times larger in area than that limited by anisoplanatism at R-band. The error budget we assemble is composed almost entirely of terms verified through independent, empirical experiments, with minimal parameterization of theoretical models. We find that error terms arising from calibration inaccuracies and optical drift are comparable in magnitude to traditional terms like fitting error and tomographic error. This makes a strong case for implementing additional calibration facilities in future AO systems, including accelerometers on powered optics, 3D turbulators, telescope and LGS simulators, and external calibration ports for deformable mirrors. These laboratory demonstrations add strong credibility to the implementation of on-sky demonstrators of Laser Tomographic Adaptive Optics (LTAO) on 5-10 meter telescopes in the coming years.

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Section: Lgs Elongationmentioning

confidence: 99%

Section: Open-loop Performance Of Wavefront Sensorsmentioning

confidence: 99%

Section: Atmospheric Phase Platesmentioning

confidence: 99%

Section: Software and Controlmentioning

confidence: 99%

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Integrated Laboratory Demonstrations of Multi-Object Adaptive Optics on a Simulated 10 Meter Telescope at Visible Wavelengths

Ammons¹,

Johnson²,

Laag³

et al. 2010

PUBL ASTRON SOC PAC

Self Cite

View full text Add to dashboard Cite

show abstract

“…For example, multiobject adaptive optics is an instrument concept that would allow highresolution imaging of a large number of faint objects across a wide field of view in an extremely large telescope. This concept would require controlling multiple DMs in an open loop because the DMs would modify the wavefront downstream of the wavefront sensor [1][2][3]. In microscopy, open-loop DM control has enabled new control approaches to nonlinear microscopy for high-resolution subsurface imaging.…”

Section: Introductionmentioning

confidence: 99%

Open-loop shape control for continuous microelectromechanical system deformable mirror

et al. 2010

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We characterize the errors associated with open-loop control of a microelectromechanical system deformable mirror (DM) using an approach that combines sparse calibration of the electrostatic actuator state space with an elastic plate model of the mirror facesheet. We quantify sources of measurement error and modeling error and demonstrate that the DM can be shaped in a single step to a tolerance of ∼8 nm of that achievable with iterative feedback-based closed-loop control. Zernike polynomials with up to 2:5 μm amplitude were made with this approach and yielded a shape error of <25 nm rms in most cases. Residual errors were shown to be due primarily to spatial resolution limits inherent in the DM (e.g., uncontrollable errors).

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Application of Hartmann linear calibrations to ViLLaGEs

et al. 2008

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Enabling laboratory demonstrations of multi-object adaptive optics with linearity calibrations

Cited by 7 publications

References 0 publications

Integrated Laboratory Demonstrations of Multi-Object Adaptive Optics on a Simulated 10 Meter Telescope at Visible Wavelengths

Integrated Laboratory Demonstrations of Multi-Object Adaptive Optics on a Simulated 10 Meter Telescope at Visible Wavelengths

Open-loop shape control for continuous microelectromechanical system deformable mirror

Application of Hartmann linear calibrations to ViLLaGEs

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