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Digital Transforms have important applications on subjects such as channel coding, cryptography and digital signal processing. In this paper, two Fourier Transforms are considered, the discrete time Fourier transform (DTFT) and the finite…

Terahertz time-domain spectroscopy (THz-TDS) has become a powerful tool for investigating the optical properties of thin films, offering direct access to the complex permittivity in the terahertz range. However, in transmission-based…

Fourier transform infrared (FTIR) spectrometers have been the dominant technology in the field of mid-infrared (MIR)spectroscopy for decades. Supercontinuum laser sources operating in the MIR spectral region now offer the potential to…

Instrumentation and Detectors · Physics 2020-04-17 Ivan Zorin , Jakob Kilgus , Kristina Duswald , Bernhard Lendl , Bettina Heise , Markus Brandstetter

Dispersive Fourier transformation is a powerful technique in which the spectrum of an optical pulse is mapped into a time-domain waveform using chromatic dispersion. It replaces a diffraction grating and detector array with a dispersive…

Optics · Physics 2009-11-13 Keisuke Goda , Kevin K. Tsia , Bahram Jalali

An accurate treatment of electronic spectra in large systems with a technique such as time dependent density functional theory (TDDFT) is computationally challenging. Due to the Nyquist sampling theorem, direct real time simulations must be…

Materials Science · Physics 2024-01-17 Matthias Kick , Ezra Alexander , Anton Beiersdorfer , Troy Van Voorhis

The resolution limits of classical spectroscopy can be surpassed by quantum-inspired methods leveraging the information contained in the phase of the complex electromagnetic field. Their counterpart in spatial imaging has been widely…

Optics · Physics 2024-09-02 Michał Lipka , Michał Parniak

The spectral characterization of quantum emitter luminescence over broad wavelength ranges and fast timescales is important for applications ranging from biophysics to quantum technologies. Here we present the application of time-domain…

Fourier Transform Interferometry (FTI) is an appealing Hyperspectral (HS) imaging modality for many applications demanding high spectral resolution, e.g., in fluorescence microscopy. However, the effective resolution of FTI is limited by…

Information Theory · Computer Science 2019-01-31 A. Moshtaghpour , L. Jacques , V. Cambareri , P. Antoine , M. Roblin

Femtosecond interferometry combined with acousto-optical phase modulation is an effective approach to implement various types of coherent nonlinear and multidimensional spectroscopy schemes. The high sensitivity of this method has recently…

Atomic Physics · Physics 2025-02-24 Friedemann Landmesser , Nicolai Gölz , Ulrich Bangert , Tobias Sixt , Lukas Bruder

We generalize the short-time Fourier transform (STFT) formalism for radial velocity extraction to cases where the underlying spectral components are unknown. The method factorizes a spectroscopic time series into principal spectra and…

Earth and Planetary Astrophysics · Physics 2026-02-17 Sahar Shahaf , Barak Zackay

High-resolution imaging in the terahertz (THz) spectral range remains fundamentally constrained by the limited numerical apertures of currently existing state-of-the-art imagers, which restricts its applicability across many fields, such as…

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

This paper introduces a spectral analysis of time-seires data derived from real-time time-dependent density functional theory (TDDFT) using Singular Spectrum Analysis (SSA). TDDFT is a robust method for obtaining molecular excited states…

Computational Physics · Physics 2025-10-02 Naoki Tani , Satoru S. Kano , Yasunari Zempo

A photonics-based short-time Fourier transform (STFT) system is proposed and experimentally demonstrated based on stimulated Brillouin scattering (SBS) without using high-frequency electronic devices and equipment. The wavelength of a…

Optics · Physics 2022-12-21 Pengcheng Zuo , Dong Ma , Yang Chen

Spectral interference, the frequency counterpart of the beating phenomenon in the time domain, can severely distort time-frequency representations (TFRs) in physical applications. We study this phenomenon for the short-time Fourier…

Classical Analysis and ODEs · Mathematics 2026-01-19 Shrikant Chand , James Nolen , Hau-Tieng Wu

Nonlinear interferometers allow for mid-infrared spectroscopy with near-infrared detection using correlated photons. Previous implementations have demonstrated a spectral resolution limited by spectrally selective detection. In our work, we…

Precision measurements of the Sunyaev-Zel'dovich effect in clusters of galaxies require excellent rejection of common-mode signals and wide frequency coverage. We describe an imaging, efficient, differential Fourier transform spectrometer…

Instrumentation and Methods for Astrophysics · Physics 2014-05-27 Alessandro Schillaci , Giuseppe D' Alessandro , Paolo de Bernardis , Silvia Masi , Camila Paiva Novaes , Massimo Gervasi , Mario Zannoni

We introduce a dual-wavelength Fourier ptychographic topography (FPT) method that extends the lambda/2 height-range limit of single-wavelength FPT. By reconstructing complex fields at two illumination wavelengths and exploiting their phase…

In many processes, the variations in underlying characteristics can be approximated by noisy multi-periodic patterns. If large-scale patterns are superimposed by a noise with long-range correlations, the detection of multi-periodic patterns…

Quantitative Methods · Quantitative Biology 2019-12-09 V. R. Chechetkin , V. V. Lobzin

Resolving sources beyond the diffraction limit is important in imaging, communications, and metrology. Current image-based methods of super-resolution require phase information (either of the source points or an added filter) and perfect…

Optics · Physics 2025-12-16 S. A. Wadood , Shaurya Aarav , Kevin Liang , Jason W Fleischer