English
Related papers

Related papers: Anisoplanatic errors in two-wavelength adaptive op…

200 papers

Context. Adaptive optics (AO) systems greatly increase the resolution of large telescopes, but produce complex point spread function (PSF) shapes, varying in time and across the field of view. This PSF must be accurately known since it…

We consider the problem of active and sequential beam tracking at mmWave frequencies and above. We focus on the dynamic scenario of a UAV to UAV communications where we formulate the problem to be equivalent to tracking an optimal…

Signal Processing · Electrical Eng. & Systems 2021-06-22 Nancy Ronquillo , Tara Javidi

Optical interferometric imaging enables astronomical observation at extremely high angular resolution. The necessary optical information for imaging, such as the optical path differences and visibilities, is easy to extract from fringes…

Orbital angular momentum (OAM) at radio frequency (RF) has attracted more and more attention as a novel approach of multiplexing a set of orthogonal OAM modes on the same frequency channel to achieve high spectral efficiency (SE). However,…

Information Theory · Computer Science 2021-12-02 Zhengjuan Tian , Rui Chen , Wen-Xuan Long , Hong Zhou , Marco Moretti

The effects of the antenna far-field power pattern limits the imaging performance of modern wide-bandwidth, high-sensitivity interferometric radio telescopes. Given a model for the aperture illumination pattern (AIP) of the antenna,…

Instrumentation and Methods for Astrophysics · Physics 2017-12-11 Preshanth Jagannathan , S. Bhatnagar , W. Brisken , A. R. Taylor

The search for exoplanets is pushing adaptive optics systems on ground-based telescopes to their limits. One of the major limitations at small angular separations, exactly where exoplanets are predicted to be, is the servo-lag of the…

A polarization-multiplexed, dual-beam setup is proposed to expand the field of view for a swept source optical coherence tomography angiography (OCTA) system. This method used a Wollaston prism to split sample path light into two…

Medical Physics · Physics 2017-10-30 Jianlong Yang , Rahul Chandwani , Rui Zhao , Zhuo Wang , Yali Jia , David Huang , Gangjun Liu

We study the impact of the atmospheric differential chromatic refraction on the measurements and precision of relative astrometry. Specifically, we address the problem of measuring the separations of close pairs of binary stars with…

Astrophysics · Physics 2009-11-13 Krzysztof G. Hełminiak

Spectrographs nominally contain a degree of quasi-static optical aberrations resulting from the quality of manufactured component surfaces, imperfect alignment, design residuals, thermal effects, and other other associated phenomena…

Instrumentation and Methods for Astrophysics · Physics 2021-07-28 Eric B. Bechter , Andrew J. Bechter , Justin R. Crepp , Jonathan Crass

Direct detection of exoplanets around nearby stars requires advanced Adaptive Optics (AO) systems. High order systems are needed to reach high Strehl Ratio (SR) in near infrared and optical wavelengths on future Giant Segmented Mirror…

Instrumentation and Methods for Astrophysics · Physics 2024-01-31 C. Vérinaud , C. T. Heritier , M. Kasper , M. Tallon

Adaptive optics (AO) are reconfigurable devices that compensate for wavefront distortions or aberrations in optical systems such as microscopes, telescopes and ophthalmoscopes. Aberrations have detrimental effects that can reduce imaging…

Optics · Physics 2025-06-10 Biwei Zhang , Martin J. Booth , Qi Hu

AOSAT is a python package for the analysis of single-conjugate adaptive optics (SCAO) simulation results. Python is widely used in the astronomical community these days, and AOSAT may be used stand-alone, integrated into a simulation…

Instrumentation and Methods for Astrophysics · Physics 2021-02-08 Markus Feldt , Stefan Hippler , Faustine Cantalloube , Thomas Bertram , Andreas Obereder , Horst Steuer , Olivier Absil , Miska Le Louarn

Differing from the traditional method of achieving subwavelength interference, we have demonstrated the two-photon subwavelength interference effect of broadband chaotic light in a polarization-selective Michelson interferometer with an…

Quantum Physics · Physics 2021-09-15 Sheng Luo , Yu Zhou , Huaibin Zheng , Wanting Xu , Jianbin Liu , Hui Chen , Yuchen He , Shuanghao Zhang , Fuli Li , Zhuo Xu

In this paper, we provide the mathematical framework to evaluate and quantify the performance of wireless systems, which employ beamforming, in the presence of hardware imperfections at both the basestation and the user equipment. In more…

Information Theory · Computer Science 2019-10-15 Alexandros-Apostolos A. Boulogeorgos , Angeliki Alexiou

The interest in using optical transition radiation (OTR) in high energy (multiGeV) beam diagnostics has motivated theoretical and experimental investigations on the limitations brought by diffraction on the attainable resolution. This paper…

Accelerator Physics · Physics 2007-05-23 X. Artru , R. Chehab , K. Honkavaara , A. Variola

Recent advancement in next generation reconfigurable antenna and fluid antenna technology has influenced the wireless system with polarization reconfigurable (PR) channels to attract significant attention for promoting beneficial channel…

Signal Processing · Electrical Eng. & Systems 2025-08-19 Seungcheol Oh , Han Han , Joongheon Kim , Sean Kwon

The point-spread function (PSF) of an adaptive optics (AO) system is often poorly known. This ignorance can lead to significant systematic errors in photometry. Since the degree of AO correction is sensitive to the observing conditions:…

Astrophysics · Physics 2010-11-11 Christopher D. Sheehy , Nate McCrady , James R. Graham

Many optical systems use acousto-optics for fast steering of light. However, acousto-optic (AO) light diffraction permits manipulation and shaping of light fields in a much broader sense including holography. While acousto-optic devices…

Optics · Physics 2022-03-15 Walther Akemann , Laurent Bourdieu

Due to turbulence in the atmosphere images taken from ground-based telescopes become distorted. With adaptive optics (AO) images can be given greater clarity allowing for better observations with existing telescopes and are essential for…

Instrumentation and Methods for Astrophysics · Physics 2023-08-30 Javier Perez Soto , Cesar Laguna , Benjamin L. Gerard , Anne Dattilo , Vincent Chambouleyron , Rebecca Jensen-Clem

The Planetary Systems Imager (PSI) is a proposed instrument for the Thirty Meter Telescope (TMT) that provides an extreme adaptive optics (AO) correction to a multi-wavelength instrument suite optimized for high contrast science. PSI's…

‹ Prev 1 8 9 10 Next ›