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Multi-mode fibers (MMFs) and single-mode fibers (SMFs) are widely used in optical communication networks. MMFs are the practical choice in terms of cost in applications that require short distances. Beyond that, SMFs are necessary because…

Optics · Physics 2023-02-22 Oussama Korichi , Markus Hiekkamäki , Robert Fickler

The next generation of large ground- and space-based optical telescopes will have segmented primary mirrors. Co-phasing the segments requires a sensitive wavefront sensor capable of measuring phase discontinuities. The Zernike wavefront…

Instrumentation and Methods for Astrophysics · Physics 2022-06-29 Maaike A. M. van Kooten , Sam Ragland , Rebecca Jensen-Clem , Yinzi Xin , Jacques-Robert Delorme , J. Kent Wallace

Optical methods based on thin multimode fibers (MMFs) are promising tools for measuring neuronal activity in deep brain regions of freely moving mice thanks to their small diameter. However, current methods are limited: while fiber…

Millimeter wave (mmWave) full-duplex (FD) is a promising technique for improving capacity by maximizing the utilization of both time and the rich mmWave frequency resources. Still, it has restrictions due to FD self-interference (SI) and…

Information Theory · Computer Science 2023-03-28 Songjie Yang , Wanting Lyu , Yunis Xanthos , Zhongpei Zhang , Chadi Assi , Chau Yuen

We propose a novel control approach that combines offline supervised learning to address the challenges posed by non-linear phase reconstruction using unmodulated pyramid wavefront sensors (P-WFS) and online reinforcement learning for…

Instrumentation and Methods for Astrophysics · Physics 2024-05-24 Bartomeu Pou , Jeffrey Smith , Eduardo Quinones , Mario Martin , Damien Gratadour

Ultrasound imaging often suffers from image degradation stemming from phase aberration, which represents a significant contributing factor to the overall image degradation in ultrasound imaging. Frequency-space prediction filtering or FXPF…

Image and Video Processing · Electrical Eng. & Systems 2023-08-24 Mostafa Sharifzadeh , Habib Benali , Hassan Rivaz

The concept of pyramid wavefront sensors (PWFS) has been around about a decade by now. However, there is still a great lack of characterizing measurements that allow the best operation of such a system under real life conditions at an…

Astrophysics · Physics 2009-11-13 D. Peter , M. Feldt , B. Dorner , T. Henning , S. Hippler , J. Aceituno

Wavefront sensing with a thin diffuser has emerged as a potential low-cost alternative to a lenslet array for aberrometry. Diffuser wavefront sensors (DWS) have previously relied on tracking speckle displacement and consequently require…

Optics · Physics 2019-01-01 Gregory N. McKay , Faisal Mahmood , Nicholas J. Durr

Imaging through optical multimode fibers (MMFs) has the potential to enable hair-thin endoscopes that reduce the invasiveness of imaging deep inside tissues and organs. Current approaches predominantly require active wavefront shaping and…

Optics · Physics 2021-12-13 Szu-Yu Lee , Vicente J. Parot , Brett E. Bouma , Martin Villiger

Future large space telescopes will be equipped with adaptive optics (AO) to overcome wavefront aberrations and achieve high contrast for imaging faint astronomical objects, such as earth-like exoplanets and debris disks. In contrast to AO…

Instrumentation and Methods for Astrophysics · Physics 2020-01-07 He Sun , N. Jeremy Kasdin , Robert Vanderbei

Increasing interest in astronomical applications of non-linear curvature wavefront sensors for turbulence detection and correction makes it important to understand how best to handle the data they produce, particularly at low light levels.…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 P. L. Aisher , J. Crass , C. Mackay

Consistent operation of adaptive optics (AO) systems requires the use of a wavefront sensor (WFS) with high sensitivity and low noise. The nonlinear curvature WFS (nlCWFS) has been shown both in simulations and lab experiments to be more…

Instrumentation and Methods for Astrophysics · Physics 2023-12-05 Sam Potier , Justin Crepp , Stanimir Letchev

Multimode optical fibers (MMFs) have gained renewed interest in the past decade, emerging as a way to boost optical communication data-rates in the context of an expected saturation of current single-mode fiber-based networks. They are also…

A crucial component of the high-contrast instrumental chain in astronomy is the wavefront sensor (WFS). A key property of this component is its sensitivities, which reflect its ability to efficiently use incoming photons to encode the phase…

Instrumentation and Methods for Astrophysics · Physics 2024-10-24 Vincent Chambouleyron , J. Kent Wallace , Rebecca Jensen-Clem , Bruce Macintosh

The James Webb Space Telescope is orders of magnitude more sensitive than any other facility across the near to mid-infrared wavelengths. Many approved programs take advantage of its highly stable point spread function (PSF) to directly…

The nonlinear curvature wavefront sensor (nlCWFS) uses multiple (typically four) out-of-focus images to reconstruct the phase and amplitude of a propagating light beam. Because these images are located between the pupil and focal planes,…

Instrumentation and Methods for Astrophysics · Physics 2024-07-23 Caleb A. Abbott , Justin R. Crepp , Stanimir O. Letchev , Connor M. Smith

The direct imaging of an Earth-like exoplanet will require sub-nanometric wavefront control across large light-collecting apertures, to reject host starlight and detect the faint planetary signal. Current adaptive optics (AO) systems, which…

Near field mmWave sensing is poised to play a key role in future wireless systems, enabling environment-aware, embodied, and application adaptive operation under stringent form-factor and hardware constraints. However, achieving high…

Information Theory · Computer Science 2026-02-09 Pin-Han Ho , Haoran Mei , Limei Peng , Yiming Miao , Xu Fan , Kairan Liang , Tong Wei , Wei Duan

Free-space optical communication (FSOC) systems offer high-bandwidth and secure communication with minimal capital costs. Adaptive optics (AO) are typically added to these systems to decrease atmospheric channel losses; however, the…

We propose and implement a broadband, compact, and low-cost wavefront sensing scheme by simply placing a thin diffuser in the close vicinity of a camera. The local wavefront gradient is determined from the local translation of the speckle…

Optics · Physics 2018-01-23 Pascal Berto , Hervé Rigneault , Marc Guillon