Results 31 to 40 of about 504,859 (272)
Spatial Spectrum Analysis of Wave-Front Correction with a Segmented Mirror [PDF]
, 2003 An expression is derived for the spatial power spectrum of wave-front errors after correction with a segmented mirror. This includes estimates of the spectral contributions of segment piston and tilt corrections and spatial aliasing by a regular array of
Padin, Stephen
core +1 more source
Atmospheric coherence times in interferometry: definition and measurement [PDF]
, 2006 Current and future ground-based interferometers require knowledge of the atmospheric time constant t_0, but this parameter has diverse definitions. Moreover, adequate techniques for monitoring t_0 still have to be implemented.
A. Kellerer +18 more
core +2 more sources
IEEE Photonics Journal, 2017 A novel approach of tip/tilt control through optimizing laser beam coupling efficiencies from space to polarization-maintaining-fibers with stochastic parallel gradient descent (SPGD) algorithm for coherent beam combining (CBC) applications is proposed ...
Feng Li +5 more
doaj +1 more source
A Demonstration of Wavefront Sensing and Mirror Phasing from the Image Domain [PDF]
, 2014 In astronomy and microscopy, distortions in the wavefront affect the dynamic range of a high contrast imaging system. These aberrations are either imposed by a turbulent medium such as the atmosphere, by static or thermal aberrations in the optical path,
Cheetham, Anthony +5 more
core +2 more sources
Operation of a MOEMS Deformable Mirror in Cryo: Challenges and Results
Micromachines, 2017 Micro-opto-electro-mechanical systems (MOEMS) Deformable Mirrors (DM) are key components for next generation optical instruments implementing innovative adaptive optics systems, both in existing telescopes and in the future ELTs.
Frederic Zamkotsian +5 more
doaj +1 more source
Piston sensing for sparse aperture systems via all-optical diffractive neural network [PDF]
arXiv, 2022 It is a crucial issue to realize real-time piston correction in the area of sparse aperture imaging. This paper introduces an optical diffractive neural network-based piston sensing method, which can achieve light-speed sensing. By using detectable intensity to represent pistons, the proposed method is capable of converting complex amplitude ...
arxiv
Tests with a Carlina-type diluted telescope; Primary coherencing [PDF]
, 2012 Studies are under way to propose a new generation of post-VLTI interferometers. The Carlina concept studied at the Haute- Provence Observatory is one of the proposed solutions. It consists in an optical interferometer configured like a diluted version of
A. Le Vansuu +37 more
core +3 more sources
Cancellation of nonrenormalizable hypersurface divergences and the d-dimensional Casimir piston [PDF]
JHEP 0709:005,2007, 2007 Using a multidimensional cut-off technique, we obtain expressions for the cut-off dependent part of the vacuum energy for parallelepiped geometries in any spatial dimension d. The cut-off part yields nonrenormalizable hypersurface divergences and we show explicitly that they cancel in the Casimir piston scenario in all dimensions.
arxiv +1 more source
High-performance 3D waveguide architecture for astronomical pupil-remapping interferometry [PDF]
, 2014 The detection and characterisation of extra-solar planets is a major theme driving modern astronomy, with the vast majority of such measurements being achieved by Doppler radial-velocity and transit observations.
Charles, Ned +8 more
core +1 more source
Piston Sensing for Sparse Aperture Systems via All-Optical Diffractive Neural Network
IEEE Photonics Journal, 2023 It is a crucial issue to realize real-time piston correction in the area of sparse aperture imaging. This paper introduces an optical diffractive neural network-based piston sensing method, which can achieve light-speed sensing. By using detectable intensity to represent pistons, the proposed method is capable of converting complex amplitude ...
Xiafei Ma +3 more
openaire +3 more sources