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We present an optical method to measure radio-frequency electro-optic phase modulation profiles by employing spectrum-to-time mapping realized by highly chirped optical pulses. We directly characterize temporal phase modulation profiles of…

Instrumentation and Detectors · Physics 2017-11-23 Michał Jachura , Jan Szczepanek , Wojciech Wasilewski , Michal Karpinski

The short-time Fourier transform (STFT) represents a window of audio samples as a set of complex coefficients. These are advantageously viewed as magnitudes and phases and the overall distribution of phases is very often assumed to be…

Audio and Speech Processing · Electrical Eng. & Systems 2024-09-16 Stephen D. Voran

We consider realistic satellite communications systems for broadband and broadcasting applications, based on frequency-division-multiplexed linear modulations, where spectral efficiency is one of the main figures of merit. For these…

Information Theory · Computer Science 2013-01-18 Amina Piemontese , Andrea Modenini , Giulio Colavolpe , Nader Alagha

Time-frequency (TF) representations of time series are intrinsically subject to the boundary effects. As a result, the structures of signals that are highlighted by the representations are garbled when approaching the boundaries of the TF…

Signal Processing · Electrical Eng. & Systems 2021-02-24 Adrien Meynard , Hau-Tieng Wu

We propose a new formalism for signal compression based on the Gabor basis set. By convolving the conventional Gabor functions with Dirichlet functions we obtain a periodic version of the Gabor basis set (pg). The pg basis is exact for…

Functional Analysis · Mathematics 2012-07-04 Asaf Shimshovitz , David J. Tannor

In this work, we perform a detailed review about the theoretical modeling of the optical propagation of ultra-short pulses in different scenarios of nonlinear optics. In particular, we focus our efforts on optical fibers and uniform media,…

Optics · Physics 2018-07-02 Andrés Macho Ortiz , Roberto Llorente Sáez

Plenty of quantum information protocols are enabled by manipulation and detection of photonic spectro-temporal degrees of freedom via light-matter interfaces. While present implementations are well suited for high-bandwidth photon sources…

This work investigates projection-based Reduced-Order Models (ROMs) formulated in the frequency domain, employing a space-time basis constructed with Spectral Proper Orthogonal Decomposition to efficiently represent dominant spatio-temporal…

Fluid Dynamics · Physics 2026-01-12 Xiaodong Li , Davide Lasagna

Existing super-resolution methods of optical imaging hold a solid place as an application in natural sciences, but many new developments allow for beating the diffraction limit in a more subtle way. One of the recently explored strategies…

Quantum Physics · Physics 2022-02-08 Mateusz Mazelanik , Adam Leszczyński , Michał Parniak

We introduce and analyze the concept of space-spectrum uncertainty for certain commonly-used designs for spectrally programmable cameras. Our key finding states that, it is impossible to simultaneously capture high-resolution spatial images…

Image and Video Processing · Electrical Eng. & Systems 2021-01-01 Vishwanath Saragadam , Aswin Sankaranarayanan

The serrodyne principle enables shifting the frequency of an electromagnetic signal by applying a linear phase ramp in the time domain [1]. This phenomenon has been exploited to frequency-shift signals in the radiofrequency (RF), microwave…

An algorithm is presented which generates pairs of oscillatory random time series which have identical periodograms but differ in the number of oscillations. This result indicate the intrinsic limitations of spectral methods when it comes…

Data Analysis, Statistics and Probability · Physics 2007-05-23 A. G. Rossberg

Scattering of ultraintense short laser pulses off relativistic electrons allows one to generate a large number of X- or $\gamma$-ray photons with the expense of the spectral width---temporal pulsing of the laser inevitable leads to…

Plasma Physics · Physics 2019-05-29 Daniel Seipt , Vasily Yu. Kharin , Sergey G. Rykovanov

Attosecond x-ray pulse with known spectro-temporal information is an essential tool for the investigation of ultrafast electron dynamics in quantum systems. Ultrafast free-electron lasers (FELs) have the unique advantage on unprecedented…

Accelerator Physics · Physics 2023-04-17 Yaozong Xiao , Hao Sun , Bo Liu , Zhentang Zhao , Chao Feng

Oscillatory processes are central for the understanding of the neural bases of cognition and behaviour. To analyse these processes, time-frequency (TF) decomposition methods are applied and non-parametric cluster-based statistical procedure…

Quantitative Methods · Quantitative Biology 2018-01-30 Christian Beste , Daniel Kaping , Tzvetomir Tzvetanov

We demonstrate a strategy for simulating wide-range X-ray scattering patterns, which spans the small- and wide scattering angles as well as the scattering angles typically used for Pair Distribution Function (PDF) analysis. Such simulated…

A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces…

We study optical pulse propagation through a hollow-core fiber filled with a radially inhomogeneous cloud of cold atoms. A co-propagating control field establishes electromagnetically induced transparency. In analogy to a graded index…

Atomic Physics · Physics 2019-07-31 Roman Sulzbach , Thorsten Peters , Reinhold Walser

The state-of-the-art automotive radars employ multidimensional discrete Fourier transforms (DFT) in order to estimate various target parameters. The DFT is implemented using the fast Fourier transform (FFT), at sample and computational…

Signal Processing · Electrical Eng. & Systems 2018-01-16 Shaogang Wang , Vishal M. Patel , Athina Petropulu

Extreme ultraviolet pulses as generated by high harmonic generation (HHG) are a powerful tool for both time-resolved spectroscopy and coherent diffractive imaging. However, the integration of spectroscopy and microscopy to harness the…