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It is shown here that precision is gained by analyzing the interferometric spectra directly from the interferograms, with no previous Fourier transformation to put them in the standard frequency domain. The method is based on the…

Instrumentation and Detectors · Physics 2018-04-20 Miguel Lagos , Rodrigo Paredes , Cesar Retamal

The power spectrum of an optical field can be acquired without a spectrally resolving detector by means of Fourier-transform spectrometry, based on measuring the temporal autocorrelation of the optical field. Analogously, we here perform…

We describe an experiment to measure the emitted real-time electric field from an ultrafast third-order nonlinear optical interaction in molecules, using a phase-tracked spectral interferometry scheme. By combining a software lock-in…

Optics · Physics 2025-03-11 Siddhant Pandey , Francis Walz , Niranjan Shivaram

Modeling non-stationary processes, where statistical properties vary across the input domain, is a critical challenge in machine learning; yet most scalable methods rely on a simplifying assumption of stationarity. This forces a difficult…

Machine Learning · Computer Science 2026-02-03 Sawan Kumar , Souvik Chakraborty

Objective detection of specific patterns in statistical distributions, like groupings or gaps or abrupt transitions between different subsets, is a task with a rich range of applications in astronomy: Milky Way stellar population analysis,…

Instrumentation and Methods for Astrophysics · Physics 2018-05-09 Roman V. Baluev

Quantum networks provide a platform for astronomical interferometers capable of imaging faint stellar objects. In a recent work [arXiv:1809.01659], we presented a protocol that circumvents transmission losses with efficient use of quantum…

Fast Fourier Transform (FFT) relies on the HRV frequency-domain analysis techniques. It requires re-sampling of the inherently unevenly sampled heartbeat time-series (RR tachogram) to produce an evenly sampled time series of the heartbeat.…

Medical Physics · Physics 2022-08-04 Amin Gasmi

The constant center frequency to bandwidth ratio (Q-factor) of wavelet transforms provides a very natural representation for audio data. However, invertible wavelet transforms have either required non-uniform decimation -- leading to…

Audio and Speech Processing · Electrical Eng. & Systems 2023-01-20 Nicki Holighaus , Günther Koliander , Clara Hollomey , Friedrich Pillichshammer

Quantum-inspired superresolution methods surpass the Rayleigh limit in imaging, or the analogous Fourier limit in spectroscopy. This is achieved by carefully extracting the information carried in the emitted optical field by engineered…

It is known that ultrasound techniques yield non-intrusive measurements of hydrodynamic flows. For example, the study of the echoes produced by a large number of particle insonified by pulsed wavetrains has led to a now standard velocimetry…

Fluid Dynamics · Physics 2009-11-07 N. Mordant , O. Michel , J. F. Pinton

We present a new method of wavelet packet decomposition to be used in gravitational wave detection. An issue in wavelet analysis is what is the time-frequency resolution which is best suited to analyze data when in quest of a signal of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Riccardo Sturani , Roberto Terenzi

In the quest for dynamic multimodal probing of a material's structure and functionality, it is critical to be able to quantify the chemical state on the atomic and nanoscale using element specific electronic and structurally sensitive tools…

Optical turbulence modelling and simulation are crucial for developing astronomical ground-based instruments, laser communication, laser metrology, or any application where light propagates through a turbulent medium. In the context of…

Instrumentation and Methods for Astrophysics · Physics 2024-04-05 A. Berdja , M. Hadjara , M. Carbillet , R. L. Bernardi , R. G. Petrov

Non-collinear four-wave mixing (FWM) techniques at near-infrared (NIR), visible, and ultraviolet frequencies have been widely used to map vibrational and electronic couplings, typically in complex molecules. However, correlations between…

Intrinsic spectrum that results from the coupling of spontaneous emission in a laser cavity, can determine the energy concentration and coherence of lasers, which is crucial for the optical high-precision measurement. Up to now, it is hard…

Theoretical analyses of ultrafast spin dynamics commonly address and discuss simulated phenomena by means of observables, whereas in quantum information theory one often utilizes measures of quantum states. In this Paper we report on…

Mesoscale and Nanoscale Physics · Physics 2023-02-15 Franziska Ziolkowski , Oliver Busch , Ingrid Mertig , Jürgen Henk

In order to efficiently image a non-absorbing sample (a phase object), dedicated phase contrast optics are required. Typically, these optics are designed with the assumption that the sample is weakly scattering, implying a linear relation…

Optics · Physics 2020-10-22 Stewart Koppell , Mark Kasevich

Ultrafast pump-probe spectroscopy is a powerful tool to study the nonequilibrium dynamics in high-Tc cuprate superconductors. The photo-induced quasiparticle (QP) dynamics revealed by pump-probe spectroscopy are sensitive to the near-Fermi…

Superconductivity · Physics 2015-06-22 Wei Li , Chunfeng Zhang , Xiaoyong Wang , Jak Chakhalian , Min Xiao

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

Despite their widespread use in cell biology, fluorescence lifetime imaging microscopy (FLIM) data-sets are challenging to analyse, because each spatial position can contain a superposition of multiple fluorescent components. Here, we…

Biological Physics · Physics 2022-08-29 Francesco Masia , Walter Dewitte , Paola Borri , Wolfgang Langbein