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In this paper an approach for decreasing the computational effort required for the split-step Fourier method (SSFM) is introduced. It is shown that using the sparsity property of the simulated signals, the compressive sampling algorithm can…

Computational Physics · Physics 2015-12-15 Cihan Bayindir

OAM spectrum reflects the OAM component included in measured light field which is crucial in OAM -based application. However, traditional definition-based OAM spectrum algorithm is extraordinary time-consuming and limited to prior knowledge…

Optics · Physics 2024-09-11 Zheng Han , Bowen Yang , Xiao Chen , Yiquan Wang

We introduce a fast Fourier spectral method for the spatially homogeneous Boltzmann equation with non-cutoff collision kernels. Such kernels contain non-integrable singularity in the deviation angle which arise in a wide range of…

Computational Physics · Physics 2020-10-28 Jingwei Hu , Kunlun Qi

A low cost scheme to determine the frequency sweep nonlinearity using atomic saturated absorption spectroscopy is demonstrated. The frequency modulation rate is determined by directly measuring the interference fringe number and frequency…

Instrumentation and Detectors · Physics 2017-10-11 Ningfang Song , Xiangxiang Lu , Xiaobin Xu , Xiong Pan , Wei Li , Di Hu , Jixun Liu

Spectra derived from fast Fourier transform (FFT) analysis of time-domain data intrinsically contain statistical fluctuations whose distribution depends on the number of accumulated spectra contributing to a measurement. The tail of this…

Solar and Stellar Astrophysics · Physics 2015-06-19 Gelu M. Nita , Gregory D. Fleishman , Dale E. Gary , William Marin , Kristine Boone

In this paper, we consider the problem of reconstructing piecewise smooth functions to high accuracy from nonuniform samples of their Fourier transform. We use the framework of nonuniform generalized sampling (NUGS) to do this, and to…

Numerical Analysis · Mathematics 2014-10-02 Ben Adcock , Milana Gataric , Anders C. Hansen

The realm of classical phase retrieval concerns itself with the arduous task of recovering a signal from its Fourier magnitude measurements, which are fraught with inherent ambiguities. A single-exposure intensity measurement is commonly…

Computer Vision and Pattern Recognition · Computer Science 2023-11-21 Yixiao Yang , Ran Tao , Kaixuan Wei , Jun Shi

Methods based on implicit neural representation have demonstrated remarkable capabilities in arbitrary-scale super-resolution (ASSR) tasks, but they neglect the potential value of the frequency domain, leading to sub-optimal performance. We…

Machine Learning · Computer Science 2025-04-29 Xufei Wang , Fei Ge , Jinchen Zhu , Mingjian Zhang , Qi Wu , Jifeng Ren Shizhuang Weng

When a plane electromagnetic wave impinges upon a diffraction grating or other periodic structures, reflected and transmitted waves propagate away from the structure in different radiation channels. A diffraction anomaly occurs when the…

Computational Physics · Physics 2022-10-05 Zitao Mai , Ya Yan Lu

We propose a new type of the Ensemble Kalman Filter (EnKF), which uses the Fast Fourier Transform (FFT) for covariance estimation from a very small ensemble with automatic tapering, and for a fast computation of the analysis ensemble by…

Atmospheric and Oceanic Physics · Physics 2011-08-01 Jan Mandel , Jonathan D. Beezley , Volodymyr Y. Kondratenko

Recently the study of modeling a non-stationary signal as a superposition of amplitude and frequency-modulated Fourier-like oscillatory modes has been a very active research area. The synchrosqueezing transform (SST) is a powerful method…

Numerical Analysis · Mathematics 2018-12-31 Haiyan Cai , Qingtang Jiang , Lin Li , Bruce W. Suter

The plane wave method is most widely used for solving the Kohn-Sham equations in first-principles materials science computations. In this procedure, the three-dimensional (3-dim) trial wave functions' fast Fourier transform (FFT) is a…

Computational Physics · Physics 2018-01-17 Xingyu Gao , Zeyao Mo , Jun Fang , Han Wang

Dispersive Fourier transformation is a powerful technique in which spectral information is mapped into the time domain using chromatic dispersion. It replaces a spectrometer with an electronic digitizer, and enables real-time spectroscopy.…

Optics · Physics 2009-11-13 J. Chou , D. R. Solli , B. Jalali

The fast Fourier transform, FFT, is a useful and prevalent algorithm in signal processing. It characterizes the spectral components of a signal, or is used in combination with other operations to perform more complex computations such as…

Signal Processing · Electrical Eng. & Systems 2017-11-08 Hani Nejadriahi , David HillerKuss , Jonathan K. George , Volker J. Sorger

An inverse nonequispaced fast Fourier transform (iNFFT) is a fast algorithm to compute the Fourier coefficients of a trigonometric polynomial from nonequispaced sampling data. However, various applications such as magnetic resonance imaging…

Numerical Analysis · Mathematics 2025-06-09 Melanie Kircheis , Daniel Potts

The nonuniform fast Fourier transform (NUFFT) generalizes the FFT to off-grid data. Its many applications include image reconstruction, data analysis, and the numerical solution of differential equations. We present FINUFFT, an efficient…

Numerical Analysis · Mathematics 2019-04-10 Alex H. Barnett , Jeremy F. Magland , Ludvig af Klinteberg

The increasing demand for data usage in wireless communications requires using wider bands in the spectrum, especially for backhaul links. Yet, allocations in the spectrum for non-communication systems inhibit merging bands to achieve wider…

Machine Learning · Computer Science 2024-11-19 Kürşat Tekbıyık , Güneş Karabulut Kurt , Antoine Lesage-Landry

The Fast Fourier Transform is extended to functions on finite graphs whose edges are identified with intervals of finite length. Spectral and pseudospectral methods are developed to solve a wide variety of time dependent partial…

Numerical Analysis · Mathematics 2025-07-11 Robert Carlson

The reported results for ultrasonic wave attenuation constant ({\alpha}) in pure water show noticeable inconsistency in magnitude. A "Propagating-Wave" model analysis of the most popular pulse-echo technique indicates that this is a…

Other Condensed Matter · Physics 2018-01-18 Barnana Pal

Nano-FTIR imaging is a powerful scanning-based technique at nanometer spatial resolution which combines Fourier transform infrared spectroscopy (FTIR) and scattering-type scanning near-field optical microscopy (s-SNOM). However, recording…

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