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We demonstrate that accurate computation of the spectral proper orthogonal decomposition (SPOD) critically depends on the choice of frequency resolution. Using both artificially generated data and large-eddy simulation data of a turbulent…

Fluid Dynamics · Physics 2024-02-27 Liam Heidt , Tim Colonius

The problem of pattern formation in resonantly-enhanced near-field lithography by the use of dielectric or plasmonic planar resonators is investigated. Sub-diffraction-limited bright or dark spots can be produced by taking advantage of the…

Optics · Physics 2008-04-22 Mankei Tsang , Demetri Psaltis

The ability to perform mathematical computations using metastructures is an emergent paradigm that carries the potential of wave-based analog computing to the realm of near-speed-of-light, low-loss, compact devices. We theoretically…

Applied Physics · Physics 2025-02-25 Dimitrios C. Tzarouchis , Brian Edwards , Nader Engheta

Optical phase conjugation (OPC) is a nonlinear technique used for counteracting wavefront distortions, with various applications ranging from imaging to beam focusing. Here, we present the design of a diffractive wavefront processor to…

Optics · Physics 2024-06-13 Che-Yung Shen , Jingxi Li , Tianyi Gan , Mona Jarrahi , Aydogan Ozcan

Optical cavities are an enabling technology of modern quantum science: from their essential role in the operation of lasers, to applications as fly-wheels in atomic clocks and interaction-enhancing components in quantum optics experiments,…

Optics · Physics 2021-08-04 Matt Jaffe , Lukas Palm , Claire Baum , Lavanya Taneja , Jonathan Simon

In this paper, we present a wideband subspace estimation method that characterizes the signal subspace through its orthogonal projection matrix at each frequency. Fundamentally, the method models this projection matrix as a function of…

Information Theory · Computer Science 2021-11-29 J. Selva

Orthogonal frequency division multiplexing (OFDM) signals with rectangularly windowed pulses exhibit low spectral confinement. Two approaches usually referred to as pulse-shaping and active interference cancellation (AIC) are classically…

Signal Processing · Electrical Eng. & Systems 2018-07-26 Luis Díez , José A. Cortés , Francisco J. Cañete , Eduardo Martos , Salvador Iranzo

Multi-object astronomical adaptive-optics (MOAO) is now a mature wide-field observation mode to enlarge the adaptive-optics-corrected field in a few specific locations over tens of arc-minutes. The work-scope provided by open-loop…

Instrumentation and Methods for Astrophysics · Physics 2023-07-19 Carlos M. Correia , Kate Jackson , Jean-Pierre Veran , David Andersen , Olivier Lardiere , Colin Bradley

This paper advocates for an innovative approach designed for estimating optoelectronic properties of quantum structures utilizing Tight-Binding (TB) theory. Predicated on the comparative analysis between estimated and actual properties, the…

Quantum Physics · Physics 2024-08-30 Ali Haji Ebrahim Zargar , Ali Amini , Ahmad Ayatollahi

Astronomical telescopes suffer from a tradeoff between field of view (FoV) and image resolution: increasing the FoV leads to an optical field that is under-sampled by the science camera. This work presents a novel computational imaging…

Instrumentation and Methods for Astrophysics · Physics 2025-08-07 Robin Swanson , Esther Y. H. Lin , Masen Lamb , Suresh Sivanandam , Kiriakos N. Kutulakos

Orthogonal Time Frequency Space (OTFS) systems face significant challenges in channel estimation due to high pilot overhead and peak-to-average power ratio (PAPR). To address these issues, we propose a two-step channel estimation method for…

Information Theory · Computer Science 2026-02-18 Omid Abbassi Aghda , Mohammad Javad Omidi , Hamid Saeedi-Sourck

We present polynomial-augmented neural networks (PANNs), a novel machine learning architecture that combines deep neural networks (DNNs) with a polynomial approximant. PANNs combine the strengths of DNNs (flexibility and efficiency in…

Machine Learning · Computer Science 2025-02-25 Madison Cooley , Shandian Zhe , Robert M. Kirby , Varun Shankar

We investigate the problem of shaping radially symmetric annular beams into desired intensity patterns along the optical axis. Within the Fresnel approximation, we show that this problem can be expressed in a variational form equivalent to…

Optimization and Control · Mathematics 2015-06-16 John A. Gemmer , Shankar C. Venkataramani , Charles G. Durfee , Jerome V. Moloney

The resonant state expansion, a recently developed method in electrodynamics, is generalized here to planar open optical systems with non-normal incidence of light. The method is illustrated and verified on exactly solvable examples, such…

Optics · Physics 2015-05-05 L. J. Armitage , M. B. Doost , W. Langbein , E. A. Muljarov

Photoacoustic computed tomography (PACT) is an emerging computed imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the absorbed optical energy density within tissue. When the imaging…

Medical Physics · Physics 2016-11-15 Qiwei Sheng , Kun Wang , Thomas P. Matthews , Jun Xia , Liren Zhu , Lihong V. Wang , Mark A. Anastasio

We obtain new quantitative estimates on Weyl Law remainders under dynamical assumptions on the geodesic flow. On a smooth compact Riemannian manifold $(M,g)$ of dimension $n$, let $\Pi_\lambda$ denote the kernel of the spectral projector…

Analysis of PDEs · Mathematics 2022-05-03 Yaiza Canzani , Jeffrey Galkowski

The Portable Adaptive Optics (PAO) is a low-cost and compact system, designed for 4-meter class telescopes that have no Adaptive Optics (AO), because of the physical space limitation at the Nasmyth or Cassegrain focus and the historically…

Instrumentation and Methods for Astrophysics · Physics 2025-12-15 Yongtian Zhu , Jiangpei Dou , Xi Zhang , Gang Zhao , Jing Guo , Leopoldo Infante

One important frontier for astronomical adaptive optics (AO) involves methods such as Multi-Object AO and Multi-Conjugate AO that have the potential to give a significantly larger field of view than conventional AO techniques. A second key…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 S. Mark Ammons , Luke Johnson , Edward A. Laag , Renate Kupke , Donald T. Gavel , Brian J. Bauman , Claire E. Max

The use of spectral projection based methods for simulation of a stochastic system with discontinuous solution exhibits the Gibbs phenomenon, which is characterized by oscillations near discontinuities. This paper investigates a dynamic…

Methodology · Statistics 2012-10-24 Piyush M. Tagade , Han-Lim Choi

A new implementation of the GW approximation (GWA) based on the all-electron Projector-Augmented-Wave method (PAW) is presented, where the screened Coulomb interaction is computed within the Random Phase Approximation (RPA) instead of the…

Materials Science · Physics 2009-11-10 S. Lebègue , B. Arnaud , M. Alouani , P. E. Bloechl