Optimal modal wave-front compensation for anisoplanatism in adaptive optics

Whiteley, Matthew R.; Welsh, Byron M.; Roggemann, Michael C.

doi:10.1364/josaa.15.002097

Cited by 27 publications

(23 citation statements)

References 31 publications

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“…(e.g. Racine & Ellerbroek 1995;Ellerbroek 1997;Whiteley et al 1998). Only a few studies focused on the anisoplanatism effect on the PSF profile, or the profile of its Fourier transform, the optical transfer function (Chassat 1992;Troxel et al 1994;Fusco et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Anisoplanatism effect on the E-ELT SCAO point spread function. A preserved coherent core across the field

Clénet

Gendron

Gratadour

et al. 2015

A&A

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Context. The science case studies and the optimized designing of the future adaptive optics-fed extremely large telescope instruments require the precise simulation of their adaptive optics system, potentially over their whole field of view, whatever the adaptive optics flavor the instruments will be equipped with. Aims. We simulate the anisoplanatism effect on the extremely large telescope single conjugate adaptive optics point spread function. Our interest in this expected degradation of the correction performance with respect to the off-axis distance is in terms of the point spread function Strehl ratio and profile. Methods. Adaptive optics simulations at the scale of extremely large telescopes are challenging given the large parameter space to explore for the adaptive optics dimensioning and the large number of degrees of freedom at play for a given set of simulation parameters. To address this problem, we have used three different simulation tools with increasing degree of fidelity compared to a real adaptive optics system. The first is based on analytical formulae and allowed us to derive the Strehl ratio degradation with the off-axis distance. The second is a Fourier-based code and provided us with both the Strehl ratio and the point spread function profile in the field. The last is an end-to-end code based on the graphical processing unit technology and also provided us with the Strehl ratio and the point spread function profile in the field. Results. The three tools we used demonstrated a fast execution time even at the extremely large telescope scale. Cross-checks between the different codes were performed and demonstrated the coherency of the results. In addition to the expected degradation of the adaptive optics performance with the field angle, we demonstrated that in the simulation conditions applicable to the E-ELT, the single conjugate adaptive optics point spread function remains topped with a coherent core even at off-axis distances as large as 60 arcsec and consequently very low Strehl ratios. We also studied the impact of the outer scale on the point spread function profile, demonstrating that the aforementioned Airy-like pattern is observable even when the outer scale is larger than the telescope diameter. Conclusions. These results could push for the preservation over a large field of the optical quality of any common path optics between the telescope and the instruments in single conjugate adaptive optics mode. This could offer some astrometric capabilities to these instruments operating in this adaptive optics mode.

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Section: Introductionmentioning

confidence: 99%

Anisoplanatism effect on the E-ELT SCAO point spread function. A preserved coherent core across the field

Clénet

Gendron

Gratadour

et al. 2015

A&A

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“…One method of measuring the aero-optic aberrations is to use the light from a guide star [6]. The guide star may be either a naturally-occurring nearby star or generated artificially using either light beacons mounted on the aircraft itself or a high-power laser beam that is focused to induce free-space air breakdown.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Beacon Anisoplanatism Through a Two-Dimensional Weakly-Compressible Shear Layer

Rennie

Whiteley

Cross

et al. 2008

39th Plasmadynamics and Lasers Conference

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An experimental investigation was conducted into the effectiveness with which aero-optic aberrations imposed on a collimated reference beam could be evaluated using a point-source beacon. The experiments were conducted in the University of Notre Dame's Compressible Shear-Layer Wind Tunnel which was used to create an optically-active shear-layer flow with high-speed Mach number of 0.8. Anisoplanatic effects included a difference in wavefront shape between the (spherical wavefront) beacon and the (planar wavefront) reference beam, and a difference in the regions of the flow sampled by the beacon and reference beams. A modal compensation approach was used to minimize the anisoplanatism between the beacon and reference wavefronts, which showed that the best compensation results were obtained when the shear layer was regularized using mechanical forcing.

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“…14 Other detailed analyses of closedloop systems are presented elsewhere. [15][16][17][18][19] 3 Concept of H ؕ Control…”

Section: Impetus For a Multivariable Controllermentioning

confidence: 99%

Theory and operation of a robust controller for a compact adaptive optics system

Tyson

2004

Opt. Eng

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We describe the design and operation of a high-speed adaptive optics system using a robust H ϱ controller. The system is also general purpose-it can be used in almost any application with minimal modifications and can be set up and operated by a minimally trained operator. The demonstrated system uses a wavefront sensor camera operating at 955 frames/s, a Xinetics 37-channel deformable mirror, and a dual processor computer to perform computations. The system exhibits control of up to 5 waves of focus, a closed-loop bandwidth of ϳ50 Hz, with a residual error of /75 rms.

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Optimal modal wave-front compensation for anisoplanatism in adaptive optics

Cited by 27 publications

References 31 publications

Anisoplanatism effect on the E-ELT SCAO point spread function. A preserved coherent core across the field

Anisoplanatism effect on the E-ELT SCAO point spread function. A preserved coherent core across the field

Measurement of Beacon Anisoplanatism Through a Two-Dimensional Weakly-Compressible Shear Layer

Theory and operation of a robust controller for a compact adaptive optics system

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