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In this article, we report an imaging method, termed Fourier ptychographic microscopy (FPM), which iteratively stitches together a number of variably illuminated, low-resolution intensity images in Fourier space to produce a wide-field,…

Optics · Physics 2014-05-02 Guoan Zheng , Roarke Horstmeyer , Changhuei Yang

Nonlinear frequency conversion provides an elegant method to detect photons in a spectral range which differs from the pump wavelength, making it highly attractive for photons with inherently low energy. Aside from the intensity of the…

Optics · Physics 2022-02-10 Tobias Pfeiffer , Jens Klier , Georg von Freymann , Daniel Molter

Frequency domain spectroscopy allows an experimenter to establish optical properties of solids in a wide frequency band including the technically challenging 10 THz region, and in other bands enables metrological comparison between…

Optics · Physics 2018-09-21 Steven Chick , Ben Murdin , Guy Matmon , Mira Naftaly

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…

We developed a coherent frequency-domain THz spectroscopic technique on a coplanar waveguide in the ultrabroad frequency range from 200 MHz to 1.6 THz based on continuous wave (CW) laser spectroscopy. Optical beating created by mixing two…

Mesoscale and Nanoscale Physics · Physics 2020-12-02 Katsumasa Yoshioka , Norio Kumada , Koji Muraki , Masayuki Hashisaka

Dispersive Fourier transformation is a powerful technique in which spectral information is mapped into the time domain using chromatic dispersion. It replaces a spectrometer with an electronic digitizer, and enables real-time spectroscopy.…

Optics · Physics 2009-11-13 J. Chou , D. R. Solli , B. Jalali

The broadband, coherent nature of narrow-linewidth fiber frequency combs is exploited to measure the full complex spectrum of a molecular gas through multi-heterodyne spectroscopy. We measure the absorption and phase shift experienced by…

Optics · Physics 2009-11-13 Ian Coddington , William C. Swann , Nathan R. Newbury

We provide a detailed description of the Herschel-SPIRE Fourier Transform Spectrometer (FTS) Spectral Feature Finder (FF). The FF is an automated process designed to extract significant spectral features from SPIRE FTS data products.…

Instrumentation and Methods for Astrophysics · Physics 2020-06-24 R. Hopwood , I. Valtchanov , Locke D. Spencer , J. P. Scott , C. S. Benson , N. Marchili , N. Hladczuk , E. T. Polehampton , N. Lu , G. Makiwa , D. A. Naylor , B. G. Gom , G. Noble , M. J. Griffin

Infrared and visible image fusion aims to utilize the complementary information from two modalities to generate fused images with prominent targets and rich texture details. Most existing algorithms only perform pixel-level or feature-level…

Computer Vision and Pattern Recognition · Computer Science 2024-10-31 Kun Hu , Qingle Zhang , Maoxun Yuan , Yitian Zhang

We show that the modulation of the phases of the laser beams of ultra-short pulses leads to modulation of the two photon fluorescence intensity. The phase modulation technique when used in multi-photon microscopy can improve the signal to…

Optics · Physics 2015-03-12 Khadga Jung Karki , Mohammed Abdellah , Tonu Pullerits

Fluorescence fluctuation spectroscopy is applied to study molecules, passing through a small observation volume, usually subjected to diffusive or convective motion in liquid phase. We suggest that such a technique could be used to measure…

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

Broadband ultrafast optical spectroscopy methods, such as transient absorption spectroscopy and 2D spectroscopy, are widely used to study molecular dynamics. However, these techniques are typically restricted to optically thick samples,…

Optics · Physics 2021-04-29 Myles C. Silfies , Grzegorz Kowzan , Neomi Lewis , Thomas K. Allison

Background: Windowed Fourier decompositions (WFD) are widely used in measuring stationary and non-stationary spectral phenomena and in describing pairwise relationships among multiple signals. Although a variety of WFDs see frequent…

Quantitative Methods · Quantitative Biology 2019-01-30 Christopher K. Kovach , Phillip E. Gander

A combination of optical feedback self-locking of a continuous-wave distributed feedback diode laser to a V-shaped high finesse cavity, laser phase modulation at a frequency equal to the free spectral range of the V-cavity and detection of…

Optics · Physics 2015-06-12 Vasili L. Kasyutich , Markus W. Sigrist

We have developed a method to equip homodyne interferometers with the capability to operate with constant high sensitivity over many fringes for continuous real-time tracking. The method can be considered as an extension of the "J_1...J_4"…

A novel phase retrieval algorithm for broadband hyperspectral phase imaging from noisy intensity observations is proposed. It utilizes advantages of the Fourier Transform spectroscopy in the self-referencing optical setup and provides,…

Image and Video Processing · Electrical Eng. & Systems 2020-06-03 Igor Shevkunov , Vladimir Katkovnik , Karen Egiazarian

As an old and widely used tool, it is still possible to find new insights and applications from Fast Fourier Transform (FFT)-based analyses. The FFT is frequently used to generate the Power Spectral Density (PSD) function, by squaring the…

Data Analysis, Statistics and Probability · Physics 2009-01-26 Sheng-Chiang Lee , Randall D. Peters

Faraday tomography, the study of the distribution of extended polarized emission by strength of Faraday rotation, is a powerful tool for studying magnetic fields in the interstellar medium of our Galaxy and nearby galaxies. The strong…

Astrophysics of Galaxies · Physics 2018-10-24 Cameron L. Van Eck

Efficient frequency conversion of photons has important applications in optical quantum technology because the frequency range suitable for photon manipulation and communication usually varies widely. Recently, an efficient frequency…