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Single Pixel (SP) imaging is now a reality in many applications, e.g., biomedical ultrathin endoscope and fluorescent spectroscopy. In this context, many schemes exist to improve the light throughput of these device, e.g., using structured…

Computer Vision and Pattern Recognition · Computer Science 2019-02-19 Amirafshar Moshtaghpour , José M. Bioucas-Dias , Laurent Jacques

Time-frequency representations, such as the short-time Fourier transform (STFT), are fundamental tools for analyzing non-stationary signals. However, their ability to achieve sharp localization in both time and frequency is inherently…

Signal Processing · Electrical Eng. & Systems 2026-04-17 David Valdivia , Elsa Cazelles , Cédric Févotte

Frequency combs have revolutionized metrology, ranging, and optical clocks, which have motivated substantial efforts on the development of chip-scale comb sources. The on-chip comb sources are currently based on electro-optic modulation,…

A fieldable dual-comb spectrometer is described based on a "bootstrapped" frequency referencing scheme in which short-term optical phase coherence between combs is attained by referencing each to a free-running diode laser, whilst high…

In many mechanical, electrical, and general physical systems evolving over time or space, spectral analysis methods as Fast Fourier Transform (FFT), Short Term Fourier Transform (STFT), Power Spectrum Density (PSD) plays a very important…

Signal Processing · Electrical Eng. & Systems 2023-06-21 Andreas Tuor , Nico Canzani , Tobias Rüggeberg , Stefan Gorenflo , Gerd Simons , Bruno Bättig , Daniel Iseli

We report a computational 3D microscopy technique, termed Fourier ptychographic diffraction tomography (FPDT), that iteratively stitches together numerous variably illuminated, low-resolution images acquired with a low-numerical aperture…

Optics · Physics 2020-02-19 Chao Zuo , Jiasong Sun , Jiaji Li , Anand Asundi , Qian Chen

Fourier transform (FT) spectroscopy is a versatile technique for studying the infrared (IR) optical response of solid-, liquid-, and gas-phase samples. In standard FT-IR spectrometers, a light beam passing through a Michelson interferometer…

Applied Physics · Physics 2021-03-12 Takashi Kuroda , Siti Chalimah , Yuanzhao Yao , Naoki Ikeda , Yoshimasa Sugimoto , Kazuaki Sakoda

We present quasi-real-time dual-comb spectroscopy (DCS) using two Yb:fiber combs with ~750 MHz repetition rates. A computational coherent averaging technique is employed to correct timing and phase fluctuations of the measured dual-comb…

A high-resolution broad-spectral-bandwidth spectrometer on a chip would create new opportunities for gas-phase molecular fingerprinting, especially in environmental sensing. A resolution high enough to observe transitions at atmospheric…

Mid-infrared optical frequency combs are of significant interest for molecular spectroscopy due to the large absorption of molecular vibrational modes on one hand, and the ability to implement superior comb-based spectroscopic modalities…

Improvements to dual-comb interferometers will benefit precision spectroscopy and sensing, distance metrology, tomography, telecommunications etc. A specific requirement of such interferometers is to enforce mutual coherence between the two…

Optics · Physics 2018-08-10 Zaijun Chen , Ming Yan , Theodor W. Hänsch , Nathalie Picqué

An integrated photonic circuit architecture to perform a modified-convolution operation based on the Discrete Fractional Fourier Transform (DFrFT) is introduced. This is accomplished by utilizing two nonuniformly-coupled waveguide lattices…

Optics · Physics 2025-02-25 Kevin Zelaya , Mohammad-Ali Miri

This study proposes and demonstrates a versatile method for near and mid-infrared optical frequency comb generation using multi-seeded femtosecond optical parametric generation. The method allows one to divide the repetition rate by an…

Optics · Physics 2022-05-25 Mikhail Roiz , Markku Vainio

This work presents a high-resolution X-ray microtomography system that uses commercial off-the-shelf (COTS) CMOS image sensors as direct detectors, relying on the sensor s intrinsic resolution to achieve tomographic reconstructions without…

Image and Video Processing · Electrical Eng. & Systems 2026-05-29 Damian L. Corzi , Jose Lipovetzky , Fabricio Alcalde Bessia , German Mato , Andres Cicuttin , Maria L. Crespo , Martin Perez , Mariano Gomez Berisso

A compact and robust coherent laser light source that provides spectral coverage from the ultraviolet to infrared is desirable for numerous applications, including heterodyne super resolution imaging[1], broadband infrared microscopy[2],…

Photonic RF transversal signal processors, which are equivalent to reconfigurable electrical digital signal processors but implemented with photonic technologies, have been widely used for modern high-speed information processing. With the…

Optics · Physics 2023-04-11 David J. Moss

The road towards the realization of quantum cascade laser (QCL) frequency combs (QCL-combs) has undoubtedly attracted ubiquitous attention from the scientific community, as these devices promise to deliver all-in-one (i.e. a single,…

Instrumentation and Detectors · Physics 2020-04-08 Luigi Consolino , Francesco Cappelli , Pablo Cancio , Iacopo Galli , Davide Mazzotti , Saverio Bartalini , Paolo De Natale

Convolutional neural networks have become an essential element of spatial deep learning systems. In the prevailing architecture, the convolution operation is performed with Fast Fourier Transforms (FFT) electronically in GPUs. The…

Emerging Technologies · Computer Science 2017-09-01 Jonathan George , Hani Nejadriahi , Volker Sorger

In the past decade, optical frequency combs generated by high-Q micro-resonators, or micro-combs, which feature compact device footprints, high energy efficiency, and high-repetition-rates in broad optical bandwidths, have led to a…

Multiheterodyne techniques using frequency combs -- light sources whose lines are perfectly evenly-spaced -- have revolutionized optical science. By beating an unknown signal with the many lines of a comb, its spectrum is recovered.…

Optics · Physics 2020-04-23 David Burghoff