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The pyramid wavefront sensor (PyWFS) has become increasingly popular to use in adaptive optics (AO) systems due to its high sensitivity. The main drawback of the PyWFS is that it is inherently nonlinear, which means that classic linear…

Instrumentation and Methods for Astrophysics · Physics 2023-11-07 Alison P. Wong , Barnaby R. M. Norris , Vincent Deo , Peter G. Tuthill , Richard Scalzo , David Sweeney , Kyohoon Ahn , Julien Lozi , Sebastien Vievard , Olivier Guyon

The performance of tomographic adaptive optics systems is intrinsically linked to the vertical profile of optical turbulence. Firstly, a sufficient number of discrete turbulent layers must be reconstructed to model the true continuous…

Instrumentation and Methods for Astrophysics · Physics 2020-04-08 O. J. D. Farley , J. Osborn , T. Morris , T. Fusco , B. Neichel , C. Correia , R. W. Wilson

Direct detection and detailed characterization of exoplanets using extreme adaptive optics (ExAO) is a key science goal of future extremely large telescopes (ELTs). However, wavefront errors will limit the sensitivity of this endeavor.…

Instrumentation and Methods for Astrophysics · Physics 2019-10-11 Benjamin L. Gerard , Christian Marois , Raphaël Galicher , Pierre Baudoz , Polychronis Patapis , Jonas Kühn

The term wavefront sensor refers to the entire class of devices capable of measuring the optical wavefront of the incoming beam. Although numerous solutions have been proposed so far, recent advances in structured light have opened new…

Adaptive Optics at mid-IR wavelengths has long been seen as either not necessary or easy. The impact of atmospheric turbulence on the performance of 8-10 meter class telescopes in the mid-IR is relatively small compared to other performance…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 R. Stuik , L. Jolissaint , S. Kendrew , S. Hippler , B. Brandl , L. Venema

The performance of an adaptive optics (AO) system on a 100m diameter ground based telescope working in the visible range of the spectrum is computed using an analytical approach. The target Strehl ratio of 60% is achieved at 0.5um with a…

Astrophysics · Physics 2009-10-31 M. Le Louarn , N. Hubin , M. Sarazin , A. Tokovinin

Context. The GRAVITY+ upgrade implies a complete renewal of its adaptive optics (AO) systems. Its complex design, featuring moving components between the deformable mirrors and the wavefront sensors, requires the monitoring and…

Focal plane wavefront sensing and control is a critical approach to reducing non-common path errors between the a conventional astronomical adaptive optics (AO) wavefront sensor (WFS) detector and science camera. However, in addition to…

Instrumentation and Methods for Astrophysics · Physics 2023-03-01 Benjamin L. Gerard , Daren Dillon , Sylvain Cetre , Rebecca Jensen-Clem

Atmospheric retrievals (AR) of exoplanets typically rely on a combination of a Bayesian inference technique and a forward simulator to estimate atmospheric properties from an observed spectrum. A key component in simulating spectra is the…

Instrumentation and Methods for Astrophysics · Physics 2023-12-20 Timothy D. Gebhard , Daniel Angerhausen , Björn S. Konrad , Eleonora Alei , Sascha P. Quanz , Bernhard Schölkopf

We discuss the chosen concepts, detailed design, implementation and calibration of the 85-electrode adaptive optics (AO) system of the Swedish 1-meter Solar Telescope (SST), which was installed in 2013. The AO system is unusual by using a…

Instrumentation and Methods for Astrophysics · Physics 2024-02-16 G. B. Scharmer , G. Sliepen , J. -C. Sinquin , M. G. Löfdahl , B. Lindberg , P. Sütterlin

Quantum key distribution (QKD) allows secure key exchange based on the principles of quantum mechanics, with higher-dimensional photonic states offering enhanced channel capacity and resilience to noise. Free-space QKD is crucial for global…

Global climate models parameterize a range of atmospheric-oceanic processes like gravity waves, clouds, moist convection, and turbulence that cannot be sufficiently resolved. These subgrid-scale closures for unresolved processes are a…

Atmospheric and Oceanic Physics · Physics 2025-09-05 Aman Gupta , Aditi Sheshadri , Sujit Roy , Johannes Schmude , Vishal Gaur , Wei Ji Leong , Manil Maskey , Rahul Ramachandran

AOLI (Adaptive Optics Lucky Imager) is a state-of-art instrument that combines adaptive optics (AO) and lucky imaging (LI) with the objective of obtaining diffraction limited images in visible wavelength at mid- and big-size ground-based…

Innovation in the ground and space-based instruments has taken us into a new age of spectroscopy, in which a large amount of stellar content is becoming available. So, automatic classification of stellar spectra became subjective in recent…

Solar and Stellar Astrophysics · Physics 2020-06-26 Y. A. Azzam , M. I. Nouh , A. A. Shaker

The Perron-Frobenius operator (PFO) is adapted from dynamical-system theory to the study of turbulent channel flow. It is shown that, as long as the analysis is restricted to the system attractor, the PFO can be used to differentiate…

Fluid Dynamics · Physics 2023-10-04 Javier Jimenez

Fluid antenna (FA) technology has emerged as a promising approach in wireless communications due to its capability of providing increased degrees of freedom (DoFs) and exceptional design flexibility. This paper addresses the challenge of…

Signal Processing · Electrical Eng. & Systems 2025-08-15 He Xu , Tuo Wu , Ye Tian , Kangda Zhi , Wei Liu , Baiyang Liu , Hing Cheung So , Naofal Al-Dhahir , Kin-Fai Tong , Chan-Byoung Chae , Kai-Kit Wong

Radial velocity instruments require high spectral resolution and extreme thermo-mecanical stability, even more difficult to achieve in near-infra red (NIR) where the spectrograph has to be cooled down. For a seeing-limited spectrograph, the…

Instrumentation and Methods for Astrophysics · Physics 2016-11-23 Uriel Conod , Nicolas Blind , François Wildi , Francesco Pepe

We present the details of predicting atmospheric turbulence by mining Zernike moment data obtained from simulations as well as experiments. Temporally correlated optical wave-fronts were simulated such that they followed Kolmogorov phase…

Instrumentation and Methods for Astrophysics · Physics 2011-09-14 Akondi Vyas , M. B. Roopashree , B. Raghavendra Prasad

Earth system predictability is challenged by the complexity of environmental dynamics and the multitude of variables involved. Current AI foundation models, although advanced by leveraging large and heterogeneous data, are often constrained…

Atmospheric and Oceanic Physics · Physics 2024-08-20 Xiao Wang , Siyan Liu , Aristeidis Tsaris , Jong-Youl Choi , Ashwin Aji , Ming Fan , Wei Zhang , Junqi Yin , Moetasim Ashfaq , Dan Lu , Prasanna Balaprakash

Traditional wavefront control in high-energy, high-intensity laser systems usually lacks real-time capability, failing to address dynamic aberrations. This limits experimental accuracy due to shot-to-shot fluctuations and necessitates long…

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