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Using time as an additional design parameter in electromagnetism, photonics, and wave physics is attracting considerable research interest, motivated by the possibility to explore physical phenomena and engineering opportunities beyond the…

Optics · Physics 2024-11-12 Matteo Ciabattoni , Zeki Hayran , Francesco Monticone

Analyzing the internal loss characteristics and multimodedness of (integrated) optical devices can prove difficult. One technique to recover this information is to Fourier transform the transmission spectrum of optical components. This…

Ultra-reliable wireless communication links require the utilization of all diversity sources of a wireless communication channel. Hadani et al. propose a two dimensional discrete symplectic Fourier transform (DSFT) as orthogonal pre-coder…

Information Theory · Computer Science 2019-07-24 Thomas Zemen , Markus Hofer , David Loeschenbrand , Christoph Pacher

This paper proposes a frequency/time hybrid integral-equation method for the time dependent wave equation in two and three-dimensional spatial domains. Relying on Fourier Transformation in time, the method utilizes a fixed…

Numerical Analysis · Mathematics 2020-04-30 Thomas G. Anderson , Oscar P. Bruno , Mark Lyon

Radio imaging is rapidly gaining prominence in the design of future communication systems, with the potential to utilize reconfigurable intelligent surfaces (RISs) as imaging apertures. Although the sparsity of targets in three-dimensional…

Information Theory · Computer Science 2024-04-09 Yixuan Huang , Jie Yang , Wankai Tang , Chao-Kai Wen , Shi Jin

In this paper we address the problem of constructing a feature extractor which combines Mallat's scattering transform framework with time-frequency (Gabor) representations. To do this, we introduce a class of frames, called uniform covering…

Functional Analysis · Mathematics 2018-02-09 Wojciech Czaja , Weilin Li

We show that to lower the sampling rate in a spread spectrum communication system using Direct Sequence Spread Spectrum (DSSS), compressive signal processing can be applied to demodulate the received signal. This may lead to a decrease in…

Information Theory · Computer Science 2012-10-11 Karsten Fyhn , Thomas Arildsen , Torben Larsen , Søren Holdt Jensen

We study the problem of sampling a random signal with sparse support in frequency domain. Shannon famously considered a scheme that instantaneously samples the signal at equispaced times. He proved that the signal can be reconstructed as…

Information Theory · Computer Science 2012-11-22 Adel Javanmard , Andrea Montanari

We describe a scalable distributed imaging algorithm framework for next-generation radio telescopes, managing the Fourier transform from apertures to sky (or vice versa) with a focus on minimising memory load, data transfers, and…

Instrumentation and Methods for Astrophysics · Physics 2024-07-17 Peter Wortmann , James Kent , Bojan Nikolic

The near-field diffraction of fs and sub-fs light pulses by nm-size slit-type apertures and its implication for near-field scanning optical microscopy (NSOM) is analyzed. The amplitude distributions of the diffracted wave-packets having the…

Optics · Physics 2013-10-11 S. V. Kukhlevsky , M. Mechler , L. Csapo

We present a structured-illumination technique for full-field super-resolution transmission X-ray microscopy, which employs Fourier spectral decomposition inspired by established methods in visible-light microscopy. A 2D grating creating…

For the realization of magnonic devices, spin-wave dispersions need to be identified. Recently, the time-resolved pump-probe imaging method combined with the Fourier transform was demonstrated for obtaining the dispersions in the…

Optics · Physics 2021-02-24 Ryo Kainuma , Keita Matsumoto , Takuya Satoh

A Python package for the calculation of spectrograms with optimized time and frequency resolution for application in the analysis of numerical simulations on ultrashort pulse propagation is presented. Gabor's uncertainty principle prevents…

Computational Physics · Physics 2018-09-05 O. Melchert , B. Roth , U. Morgner , A. Demircan

The design of a compact high-speed and wide field of view (FOV) receiver is challenging due to the presence of two well-known trade-offs. The first one is the area-bandwidth trade-off of photodetectors (PDs) and the second one is the…

We present a new technique using a frequency comb laser and optical cavities for performing ultrafast transient absorption spectroscopy with improved sensitivity. Resonantly enhancing the probe pulses, we demonstrate a sensitivity of…

Optics · Physics 2016-04-05 Melanie A. R. Reber , Yuning Chen , Thomas K. Allison

Information about microscopic objects with features smaller than the diffraction limit is almost entirely lost in a far-field diffraction image but could be partly recovered with data completition techniques. Any such approach critically…

Optics · Physics 2020-11-17 Maria Bancerek , Krzysztof M. Czajkowski , Rafal Kotynski

The far-field subwavlength imaging is a challenging issue. In this letter we demonstrate numerically that the far-field subwavelength imaging of weakly scattering objects can be obtained by processing the data acquired by a single antenna,…

Optics · Physics 2014-01-20 Lianlin Li , Fang Li , Tie Jun Cui

Compressed sensing has shown great potential in reducing data acquisition time in magnetic resonance imaging (MRI). Recently, a spread spectrum compressed sensing MRI method modulates an image with a quadratic phase. It performs better than…

Computer Vision and Pattern Recognition · Computer Science 2016-01-27 Xiaobo Qu , Ying Chen , Xiaoxing Zhuang , Zhiyu Yan , Di Guo , Zhong Chen

In this letter we study the subwavelength imaging of sparse broadband sources inside a disordered medium by processing the data acquired by a single antenna. A mathematical model has been developed for solving such problem based on the idea…

Optics · Physics 2015-06-18 Lianlin Li , Fang Li , Tie Jun Cui

We present measurements of the complete spatio-temporal Fourier spectrum of Faraday waves. The Faraday waves are generated at the interface of two immiscible index matched liquids of different density. By use of a new absorption technique…

Pattern Formation and Solitons · Physics 2009-11-11 A. V. Kityk , E. Embs , V. V. Mekhonoshin , C. Wagner