&lt;title&gt;Fitting capability of deformable mirror&lt;/title&gt;

Jiang, Wenhan; Ning, Lixin; Rao, Xuejun; Shi, Fangtian

doi:10.1117/12.48800

Cited by 31 publications

(13 citation statements)

References 1 publication

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“…9,10 The variable A is the amplitude of the deflection, a is the coupling coefficient of the actuators, r is the aperture diameter, r i is the actuator location and r s is the actuator spacing. The deflection amplitude is set to 2.5 times the peak-to-valley (PTV) residual wavefront error of SMT.…”

Section: Simulationmentioning

confidence: 99%

Correction of active space telescope mirror using woofer-tweeter adaptive optics

2015

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Future large aperture space telescopes may use lightweight correctable active mirrors. The Naval Postgraduate School's Segmented Mirror Telescope (SMT) test bed uses 1-meter silicon carbide (SiC) active mirror segments to form a sixsegment deployable 3-meter telescope. The active segments suffer from residual surface errors after a correction is applied. A deformable mirror is added at the SMT pupil plane to improve this residual error. The large active SMT segment represents the woofer, and a small continuous micro-electro-mechanical system (MEMS) deformable mirror represents the tweeter. A global influence matrix and closed loop constrained least squares controller command the active segment and additional deformable mirror as a single device. An interferometer measures the surface error and provides feedback to the controller. Simulation and experimental results demonstrate a significant improvement in wavefront error compared to a 2-step sequential woofer-tweeter constrained least squares control approach.

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Section: Simulationmentioning

confidence: 99%

Correction of active space telescope mirror using woofer-tweeter adaptive optics

2015

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“…On the basis of real measurements, we know that the response function of 61-element deformable mirror actuators is Gaussian distribution approximately [13]. Figure 3 gives the location distribution of 61-element DM actuators.…”

Section: Startmentioning

confidence: 99%

Performance Comparison of Wavefront-Sensorless Adaptive Optics Systems by Using of the Focal Plane

Yang

Zhang

2015

International Journal of Optics

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The correction capability and the convergence speed of the wavefront-sensorless adaptive optics (AO) system are compared based on two different system control algorithms, which both use the information of focal plane. The first algorithm is designed through the linear relationship between the second moment of the aberration gradients and the masked far-field intensity distribution and the second is stochastic parallel gradient descent (SPGD), which is the most commonly used algorithm in wavefront-sensorless AO systems. A wavefront-sensorless AO model is established with a 61-element deformable mirror (DM) and a CCD. Performance of the two control algorithms is investigated and compared through correcting different wavefront aberrations. Results show that the correction ability of AO system based on the proposed control algorithm is obviously better than that of AO system based on SPGD algorithm when the wavefront aberrations increase. The time needed by the proposed control algorithm is much less than that of SPGD when the AO system achieves similar correction results. Additionally, the convergence speed of the proposed control algorithm is independent of the turbulence strength while the number of intensity measurements needed by SPGD increases as the turbulence strength magnifies.

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“…where u j is the voltage applied onto the jth actuator, and V j x; y is the influence function of the jth actuator on the wavefront, which can be approximately expressed as a Gaussian distribution [19]: …”

Section: Estimating Fried's Parameter Using Spgd Algorithmmentioning

confidence: 99%

Estimating the atmospheric correlation length with stochastic parallel gradient descent algorithm

2014

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The atmospheric turbulence measurement has received much attention in various fields due to its effects on wave propagation. One of the interesting parameters for characterization of the atmospheric turbulence is the Fried parameter or the atmospheric correlation length. We numerically investigate the feasibility of estimating the Fried parameter using a simple and low-cost system based on the stochastic parallel gradient descent (SPGD) algorithm without the need for wavefront sensing. We simulate the atmospheric turbulence using Zernike polynomials and employ a wavefront sensor-less adaptive optics system based on the SPGD algorithm and report the estimated Fried parameter after compensating for atmospheric-turbulence-induced phase distortions. Several simulations for different atmospheric turbulence strengths are presented to validate the proposed method.

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<title>Fitting capability of deformable mirror</title>

Cited by 31 publications

References 1 publication

Correction of active space telescope mirror using woofer-tweeter adaptive optics

Correction of active space telescope mirror using woofer-tweeter adaptive optics

Performance Comparison of Wavefront-Sensorless Adaptive Optics Systems by Using of the Focal Plane

Estimating the atmospheric correlation length with stochastic parallel gradient descent algorithm

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