Results 11 to 20 of about 142,915 (284)

On-sky results of the adaptive optics MACAO for the new IR-spectrograph CRIRES at VLT [PDF]

open access: yes, 2006
The adaptive optics MACAO has been implemented in 6 focii of the VLT observatory, in three different flavors. We present in this paper the results obtained during the commissioning of the last of these units, MACAO-CRIRES.
Biereichel, P.   +18 more
core   +3 more sources

Experimental Demonstration of Central-Lobe Energy Enhancement Based on Amplitude Modulation of Beamlets in 19 Elements Fiber Laser Phased Array

open access: yesIEEE Photonics Journal, 2021
Coherent beam combination of fiber laser phased array is a promising technique to achieve high-brightness laser output. In this paper, we focus on central-lobe energy enhancement of the combined beam in the far-field by theoretically and experimentally ...
Jing Zuo   +11 more
doaj   +1 more source

ALFA: First Operational Experience of the MPE/MPIA Laser Guide Star System for Adaptive Optics [PDF]

open access: yes, 1998
The sodium laser guide star adaptive optics system ALFA has been constructed at the Calar Alto 3.5-m telescope. Following the first detection of the laser beacon on the wavefront sensor in 1997 the system is now being optimized for best performance.
Davies, R. I.   +7 more
core   +3 more sources

An Image-Based Alignment Errors Correction Method for Segmented Fresnel Primary Mirror

open access: yesIEEE Photonics Journal, 2020
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,
Licheng Zhu   +5 more
doaj   +1 more source

Shack–Hartmann Wavefront Sensing Based on Four-Quadrant Binary Phase Modulation

open access: yesPhotonics, 2022
Aiming at the problem that it is difficult for the conventional Shack–Hartmann wavefront sensor to achieve high-precision wavefront reconstruction with low spatial sampling, a kind of Shack–Hartmann wavefront sensing technology based on four-quadrant ...
Mengmeng Zhao   +7 more
doaj   +1 more source

Adaptive Optics Tip-Tilt Correction Based on Smith Predictor and Filter-Optimized Linear Active Disturbance Rejection Control Method

open access: yesSensors, 2023
A tip-tilt mirror (TTM) control method is designed to enhance the control bandwidth and ensure the rejection performance of the adaptive optics (AO) tip-tilt correction system.
Lingxi Kong   +6 more
doaj   +1 more source

PASSATA - Object oriented numerical simulation software for adaptive optics [PDF]

open access: yes, 2016
We present the last version of the PyrAmid Simulator Software for Adaptive opTics Arcetri (PASSATA), an IDL and CUDA based object oriented software developed in the Adaptive Optics group of the Arcetri observatory for Monte-Carlo end-to-end adaptive ...
Agapito, G., Esposito, S., Puglisi, A.
core   +2 more sources

Centroid-Predicted Deep Neural Network in Shack-Hartmann Sensors

open access: yesIEEE Photonics Journal, 2022
The Shack-Hartmann wavefront sensor produces incorrect wavefront measurements when some sub-spots are weak and missing. In this paper, a method is proposed to predict the centroids of these sub-spots for the Shack-Hartmann wavefront sensor based on the ...
Mengmeng Zhao   +6 more
doaj   +1 more source

Adaptive Optics for Extremely Large Telescopes

open access: yes, 2019
Adaptive Optics has become a key technology for the largest ground-based telescopes currently under or close to begin of construction. Adaptive optics is an indispensable component and has basically only one task, that is to operate the telescope at its ...
Hippler, Stefan
core   +1 more source

Design and Experimental Validation of a Model-Free Controller for Beam Stabilization in Adaptive Optics Systems

open access: yesIEEE Photonics Journal
Stabilization of optical beams has always been a key factor affecting the performance of many optical systems. The Adaptive optics (AO) beam stabilization system requires further development to cope with increasingly complex application scenarios and ...
Sicheng Guo   +6 more
doaj   +1 more source

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