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Dual-comb spectroscopy is a promising method for precise optical spectrum analysis with fast data acquisition speed. However, its implementation and applications are often hindered by the complexity of optical comb systems. Here, as a…

Optics · Physics 2020-11-11 Zhen Zhang , Haiyun Xia , Saifen Yu , Lijie Zhao , Tianwen Wei , Manyi Li

Fourier-transform infrared spectroscopy (FTIR) is the golden standard of mid-infrared (MIR) molecular spectroscopic analysis through optically-encoded vibrational signatures. Michelson-type FTIR and MIR dual-comb spectrometers allow us to…

Optics · Physics 2025-05-06 Kazuki Hashimoto , Venkata Ramaiah Badarla , Takuro Ideguchi

In recent years, the synchrosqueezing transform (SST) has gained popularity as a method for the analysis of signals that can be broken down into multiple components determined by instantaneous amplitudes and phases. One such version of SST,…

Numerical Analysis · Mathematics 2017-09-20 Alexander Berrian , Naoki Saito

We present the development and performance of a Fourier transformation (FT) based Raman spectrometer working with visible laser (532 nm) excitation. It is generally thought that FT-Raman spectrometers are not viable in the visible range…

Transverse deflecting structures (TDS) are widely used in accelerator physics to measure the longitudinal density of particle bunches. When used in combination with a dispersive section, the whole longitudinal phase space density can be…

Sub-terahertz (Sub-THz) waves possess exceptional attributes, capable of penetrating non-metallic and non-polarized materials while ensuring bio-safety. However, their practicality in imaging is marred by the emergence of troublesome…

Optics · Physics 2024-03-07 Shao-Hsuan Wu , Yiyao Zhang , Ke Chen , Shang Hua Yang

The general space-time evolution of the scattering of an incident acoustic plane wave pulse by an arbitrary configuration of targets is treated by employing a recently developed non-singular boundary integral method to solve the Helmholtz…

Computational Physics · Physics 2017-10-11 Evert Klaseboer , Shahrokh Sepehrirahnama , Derek Y. C. Chan

Photothermal-Induced Resonance (PTIR) is increasingly used in the measurement of infrared absorption spectra of sub-micrometer objects. The technique measures IR absorption spectra by relying on the photothermal effect induced by a rapid…

Chemical Physics · Physics 2019-11-28 Luca Quaroni

The Herschel SPIRE Fourier transform spectrometer (FTS) performs spectral imaging in the 447-1546 GHz band. It can observe in three spatial sampling modes: sparse mode, with a single pointing on sky, or intermediate or full modes with 1 and…

We propose Fourier transform (FT) method for processing images of extensive air showers (EAS) detected by imaging atmospheric Cherenkov telescopes (IACT) used in the very high energy (VHE) gamma-ray astronomy. The method is based on the…

Astrophysics · Physics 2009-11-10 A. Atoyan , J. Patera , V. Sahakian , A. Akpherjanian

Optical microscopy has so far been restricted to superficial layers, leaving many important biological questions unanswered. Random scattering causes the ballistic focus, which is conventionally used for image formation, to decay…

Optics · Physics 2012-08-28 Ke Si , Reto Fiolka , Meng Cui

Near-field imaging with terahertz (THz) waves is emerging as a powerful technique for fundamental research in photonics and across physical and life sciences. Spatial resolution beyond the diffraction limit can be achieved by collecting THz…

In the presence of additive Gaussian noise, the statistics of the nonlinear Fourier transform (NFT) of a pulse are not yet completely known in closed form. In this paper, we propose a novel approach to study this problem. Our contributions…

Information Theory · Computer Science 2019-05-22 Francisco Javier Garcia-Gomez , Vahid Aref

The near-field diffraction of fs and sub-fs light pulses by nm-size slit-type apertures and its implication for near-field scanning optical microscopy (NSOM) is analyzed. The amplitude distributions of the diffracted wave-packets having the…

Optics · Physics 2013-10-11 S. V. Kukhlevsky , M. Mechler , L. Csapo

The standing waves existed in radio telescope data are primarily due to reflections among the instruments, which significantly impact the spectrum quality of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Eliminating…

Instrumentation and Methods for Astrophysics · Physics 2025-01-09 Chen Xu , Jie Wang , Yingjie Jing , Fujia Li , Hengqian Gan , Ziming Liu , Tiantian Liang , Qingze Chen , Zerui Liu , Zhipeng Hou , Hao Hu , Huijie Hu , Shijie Huang , Peng Jiang , Chuan-Peng Zhang , Yan Zhu

The principles and practice of astronomical imaging Fourier transform spectroscopy (FTS) at far-infrared wavelengths are described. The Mach-Zehnder interferometer design has been widely adopted for current and future imaging FTS…

Instrumentation and Methods for Astrophysics · Physics 2013-10-10 David A. Naylor , Brad G. Gom , Matthijs H. D. van der Wiel , Gibion Makiwa

We present a brief technical outline of the newly-formed 'Detection of Spectroscopic Differences over Time' (DS/DT) project. Our collaboration is using the individual exposures from the SDSS spectroscopic archive to produce a…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 Steven Bickerton , Carles Badenes , Thomas Hettinger , Timothy Beers , Sonya Huang

We describe an update to the Herschel-SPIRE Fourier-Transform Spectrometer (FTS) calibration for extended sources, which incorporates a correction for the frequency-dependent far-field feedhorn efficiency, $\eta_\mathrm{FF}$. This…

Mode-resolved dual-comb spectroscopy (DCS) is an emerging spectroscopic tool with the potential to simultaneously achieve a broad spectral coverage and ultrahigh spectral resolution in terahertz (THz) spectroscopy. However, the need for two…

Instrumentation and Detectors · Physics 2020-06-02 Jie Chen , Kazuki Nitta , Xin Zhao , Takahiko Mizuno , Takeo Minamikawa , Francis Hindle , Zheng Zheng , Takeshi Yasui

The goal of this thesis was to develop a procedure to optimize the mirror suppression, which reduces the dynamic range of the Fast Fourier Transform spectrometers (FFTS), and implement this procedure in the Field Programmable Gate Array…

Instrumentation and Methods for Astrophysics · Physics 2022-08-23 Gerrit Grutzeck