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Coordinating the operations of separate wireless systems at the wavelength level can lead to significant improvements in wireless capabilities. We address a fundamental challenge in distributed radio frequency system cooperation -…

Signal Processing · Electrical Eng. & Systems 2020-10-21 Serge R. Mghabghab , Sean M. Ellison , Jeffrey A. Nanzer

The Fractional Fourier Transform (FRT) corresponds to an arbitrary-angle rotation in the phase space, e.g. the time-frequency (TF) space, and generalizes the fundamentally important Fourier Transform. FRT applications range from classical…

Optics · Physics 2024-03-06 Michał Lipka , Michał Parniak

Researchers from a broad spectrum of scientific and engineering disciplines are increasingly using near-field infrared spectroscopic techniques to characterize materials nondestructively and with nanoscale spatial resolution. However,…

Optics · Physics 2023-03-21 Jonathan M. Larson , Hans A. Bechtel , Robert Kostecki

Interferometric scattering (iSCAT) microscopy is an emerging label-free technique optimized for the sensitive detection of nano-matter. Previous iSCAT studies have approximated the point spread function in iSCAT by a Gaussian intensity…

In this paper, we present an assortment of both standard and advanced Fourier techniques that are useful in the analysis of astrophysical time series of very long duration -- where the observation time is much greater than the time…

Astrophysics · Physics 2009-11-07 Scott M. Ransom , Stephen S. Eikenberry , John Middleditch

The combination of grating-based frequency-selective optical feedback mechanisms, such as distributed feedback (DFB) or distributed Bragg reflector (DBR) structures, with quantum dot (QD) gain materials is a main approach towards…

In radar systems, high resolution in the Doppler dimension is important for detecting slow-moving targets as it allows for more distinct separation between these targets and clutter, or stationary objects. However, achieving sufficient…

Computer Vision and Pattern Recognition · Computer Science 2025-05-26 Denisa Qosja , Kilian Barth , Simon Wagner

The frequency-dependent optical spectrum is pivotal for a broad range of applications, from material characterization to optoelectronics and energy harvesting. Data-driven surrogate models, trained on density functional theory (DFT) data,…

Chemical Physics · Physics 2024-07-11 Akram Ibrahim , Can Ataca

A Discrete Fourier Transform Method (DFTM) for discrimination between the signal of neutrons and gamma rays in organic scintillation detectors is presented. The method is based on the transformation of signals into the frequency domain…

Instrumentation and Detectors · Physics 2016-11-03 M. J. Safari , F. Abbasi Davani , H. Afarideh , S. Jamili , E. Bayat

We propose a new kind of interferometric array that yields images of high dynamic range and large field. The numerous individual apertures in this array form a pattern related to a Fresnel zone plate. This array can be used for…

Astrophysics · Physics 2009-11-11 L. Koechlin , D. Serre , P. Duchon

Superconducting On-chip Fourier Transform Spectrometers (SOFTS) are broadband, compact and electronic interferometers. Being extremely compact, SOFTS can fit into standard antenna coupled detector architectures. SOFTS will enable kilo-pixel…

Instrumentation and Methods for Astrophysics · Physics 2022-12-21 R. Basu Thakur , A. Steiger , S. Shu , F. Faramarzi , N. Klimovich , P. K. Day , E. Shirokoff , P. D. Mauskopf , P. S. Barry

In this paper, we propose a new convolutional layer called Depthwise-STFT Separable layer that can serve as an alternative to the standard depthwise separable convolutional layer. The construction of the proposed layer is inspired by the…

Computer Vision and Pattern Recognition · Computer Science 2020-01-29 Sudhakar Kumawat , Shanmuganathan Raman

Detrend fluctuation analysis (DFA) has become a choice method for effective analysis of a broad variety of nonstationary signals. We show in the present article that, provided the nonstationary fluctuations occur at a large enough time…

Quantitative Methods · Quantitative Biology 2007-05-23 Luciano da Fontoura Costa , Ruth Caldeira de Melo , Ester da Silva , Audrey Borghi-Silva , Aparecida Maria Catai

We present an implementation of the coherent dedispersion algorithm capable of dedispersing high-time-resolution radio observations to many different dispersion measures (DMs). This approach allows the removal of the dispersive effects of…

Instrumentation and Methods for Astrophysics · Physics 2016-07-05 C. G. Bassa , Z. Pleunis , J. W. T. Hessels

We present a differentiation framework for plane-wave density-functional theory (DFT) that combines the strengths of forward-mode algorithmic differentiation (AD) and density-functional perturbation theory (DFPT). In the resulting AD-DFPT…

Materials Science · Physics 2025-12-23 Niklas Frederik Schmitz , Bruno Ploumhans , Michael F. Herbst

We develop the uniform sparse Fast Fourier Transform (usFFT), an efficient, non-intrusive, adaptive algorithm for the solution of elliptic partial differential equations with random coefficients. The algorithm is an adaption of the sparse…

Numerical Analysis · Mathematics 2022-09-05 Lutz Kämmerer , Daniel Potts , Fabian Taubert

We provide the first demonstration that a neutron far-field interferometer can be employed to measure the microstructure of a sample. The interferometer is based on the moir\'e pattern of two phase modulating gratings which was previously…

The far-infrared (IR) region is rich with information needed to characterize interstellar dust and to investigate the cold outer planets of the solar system and their icy moons. The proposed sub-orbital observatory the Balloon Experiment…

Instrumentation and Methods for Astrophysics · Physics 2023-12-27 Joanna Perido , Kevin Denis , Jason Glenn , Nicholas F. Cothard , Manuel Quijada , Jessica Patel , Edward Wollack , Tilak Hewagama , Shahid Aslam , Peter K. Day

High-precision spectrophotometry is highly desirable in detecting and characterizing close-in extrasolar planets to learn about their makeup and temperature. For such a goal, a modest-size telescope with a simple low-resolution…

Astrophysics · Physics 2009-11-07 M. A. Kenworthy , P. M. Hinz

We propose a method for tailoring the frequency spectrum of bright squeezed vacuum by generating it in a nonlinear interferometer, consisting of two down-converting nonlinear crystals separated by a dispersive medium. Due to a faster…

Quantum Physics · Physics 2016-01-20 T. Sh. Iskhakov , S. Lemieux , A. Perez , R. W. Boyd , G. Leuchs , M. Chekhova