Results 51 to 60 of about 43,714 (202)

Reinforcement Learning Environment for Wavefront Sensorless Adaptive Optics in Single-Mode Fiber Coupled Optical Satellite Communications Downlinks

Photonics, 2023
Optical satellite communications (OSC) downlinks can support much higher bandwidths than radio-frequency channels. However, atmospheric turbulence degrades the optical beam wavefront, leading to reduced data transfer rates.
Payam Parvizi, Runnan Zou, Colin Bellinger, Ross Cheriton, Davide Spinello   +4 more
doaj   +1 more source

Centroid Detection by Gaussian Pattern Matching in Adaptive Optics [PDF]

, 2009
Shack Hartmann wavefront sensor is a two dimensional array of lenslets which is used to detect the incoming phase distorted wavefront through local tilt measurements made by recording the spot pattern near the focal plane.
Prasad, B Raghavendra, Roopashree, M B, Vyas, Akondi   +2 more
core   +1 more source

Joint optimization of wavefront sensing and reconstruction with automatic differentiation [PDF]

arXiv, 2022
High-contrast imaging instruments need extreme wavefront control to directly image exoplanets. This requires highly sensitive wavefront sensors which optimally make use of the available photons to sense the wavefront. Here, we propose to numerically optimize Fourier-filtering wavefront sensors using automatic differentiation.
arxiv  

Wavefront Reconstruction of Shack-Hartmann with Under-Sampling of Sub-Apertures

Photonics, 2023
Shack-Hartmann wavefront sensor plays a key role in adaptive optics (AO) systems, which detect the aberrant wavefront by an array of micro-lenslets across the aperture pupil.
Jian Huang, Lianqun Yao, Shuyun Wu, Gongchang Wang   +3 more
doaj   +1 more source

Small Mirrors for Small Satellites: Design of the Deformable Mirror Demonstration Mission CubeSat (DeMi) Payload

Frontiers in Astronomy and Space Sciences, 2021
The Deformable Mirror Demonstration Mission (DeMi) is a technology demonstration CubeSat to test a 140 actuator micro-electromechanical system (MEMS) deformable mirror in low-Earth orbit.
Ewan S. Douglas, Ewan S. Douglas, Greg Allan, Rachel Morgan, Bobby G. Holden, Jennifer Gubner, Christian Haughwout, Paula do Vale Pereira, Yinzi Xin, Yinzi Xin, John Merk, Kerri L. Cahoy, Kerri L. Cahoy   +12 more
doaj   +1 more source

Multiple guide star tomography demonstration at Palomar observatory [PDF]

, 2006
We have built and field tested a multiple guide star tomograph with four Shack-Hartmann wavefront sensors. We predict the wavefront on the fourth sensor channel estimated using wavefront information from the other three channels using synchronously ...
Britton, M. C., Dekany, R. G., Flicker, R. C., Hickey, J., Platt, B. C., Roberts, J. E., Shelton, J. C., Troy, M., Velur, V.   +8 more
core   +1 more source

Turbulent parameters at different heights in the atmosphere. Shack–Hartmann wavefront sensor data

Solar-Terrestrial Physics, 2022
The paper presents the results of studies of wavefront distortions at different heights in the atmosphere. We have used measurement wavefront data to determine optical turbulence parameters along the line of sight of the Large Solar Vacuum Telescope ...
Shikhovtsev A. Y., Kiselev A. V., Kovadlo P. G., Kolobov D. Y., Russkikh I. V., Tomin V. E   +5 more
doaj   +1 more source

A CMOS-based Hartmann-Shack Sensor for Real-Time Adaptive Optical Applications [PDF]

, 2003
Adaptive optical systems have a growing field of applications in opthalmology. In every adaptive system there is the need for a sensor and an actuator.
Nirmaier, Thomas
core   +1 more source

Parafoveal and Perifoveal Accommodation Response to Defocus Changes Induced by a Tunable Lens

Applied Sciences, 2023
The accommodative response of the human eye is predominantly driven by foveal vision, but reacts also to off-foveal stimuli. Here, we report on monocular accommodation measurements using parafoveal and perifoveal annular stimuli centered around the fovea
Najnin Sharmin, Petros Papadogiannis, Dmitry Romashchenko, Linda Lundström, Brian Vohnsen   +4 more
doaj   +1 more source

Adaptive Optics Correction of the Wavefront Distortions Induced by Segments Misalignment in Extremely Large Telescope [PDF]

, 2006
The capability of the adaptive optics to correct for the segmentation error is analyzed in terms of the residual wavefront RMS and the power spectral density of the phase.
Verinaud, Christophe, Yaitskova, Natalia
core   +2 more sources