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We present a novel approach for the inverse problem in electrical impedance tomography based on regularized quadratic regression. Our contribution introduces a new formulation for the forward model in the form of a nonlinear integral…

Geophysics · Physics 2012-05-29 Nick Polydorides , Alireza Aghasi , Eric L. Miller

Heavy sweep distortion induced by alignments and inter-reflections of layers of a sample is a major burden in recovering 2D and 3D information in time resolved spectral imaging. This problem cannot be addressed by conventional denoising and…

Computer Vision and Pattern Recognition · Computer Science 2016-04-13 Alireza Aghasi , Barmak Heshmat , Albert Redo-Sanchez , Justin Romberg , Ramesh Raskar

Terahertz (THz) communication is envisioned as one of the candidate technologies for future wireless communications to enable achievable data rates of up to several terabits per second (Tbps). However, the high pathloss and molecular…

Signal Processing · Electrical Eng. & Systems 2024-03-14 Muddasir Rahim , Thanh Luan Nguyen , Georges Kaddoum , Tri Nhu Do

THz time domain spectroscopy is a powerful technique enabling the investigation of different materials in the far-infrared frequency range. Even if nowadays this technique is well established, its application to very thin films remains…

Instrumentation and Detectors · Physics 2024-06-07 A. Taschin , P. Bartolini , J. Tasseva , R. Torre

In order to determine the 3D structure of a thick sample, researchers have recently combined ptychography (for high resolution) and tomography (for 3D imaging) in a single experiment. 2-step methods are usually adopted for reconstruction,…

Image and Video Processing · Electrical Eng. & Systems 2020-07-21 Huibin Chang , Pablo Enfedaque , Stefano Marchesini

Using a 3D fully-vectorial nonlinear time-domain analysis we numerically investigate the generation of terahertz radiation by pumping a photonic crystal microcavity out of resonance. High quality factors and a quadratic susceptibility lead…

Optics · Physics 2009-11-11 Andrea Di Falco , Claudio Conti , Gaetano Assanto

Medical imaging modalities have revolutionized health-care approaches by offering a better understanding of the human anatomy. Discovery of x-rays allowed the exploiting of the micro-scaled information of human anatomy. Computed tomography…

Medical Physics · Physics 2018-09-18 Sanam Assili

In this article we study the inverse problem of thermoacoustic tomography (TAT) on a medium with attenuation represented by a time- convolution (or memory) term, and whose consideration is motivated by the modeling of ultrasound waves in…

Analysis of PDEs · Mathematics 2017-03-29 Sebastian Acosta , Benjamin Palacios

Inspired by the extensive application of terahertz imaging technologies in the field of aerospace, we exploit a terahertz frequency modulated continuous wave imaging method with continuous wavelet transform algorithm to detect a multilayer…

Signal Processing · Electrical Eng. & Systems 2019-05-30 Yu Zhou

A method to reconstruct weakly anisotropic inhomogeneous dielectric tensors inside a transparent medium is proposed. The mathematical theory of Integral Geometry is cast into a workable framework which allows the full determination of…

Optics · Physics 2009-11-10 Hanno Hammer , William R. B. Lionheart

Continuous Wave (CW) Terahertz spectroscopy enabled by photomixing is a promising high precision spectroscopic tool for the examination of a wide variety of samples including biological, chemical, and solid state. However, often it would be…

Optics · Physics 2022-12-06 James Seddon , Chris Graham , Marie Georgiades , Cyril Renaud , Alwyn Seeds

Compressed Sensing based Terahertz imaging (CS-THz) is a computational imaging technique. It uses only one THz receiver to accumulate the random modulated image measurements where the original THz image is reconstruct from these…

Computer Vision and Pattern Recognition · Computer Science 2013-09-25 Benyuan Liu , Hongqi Fan , Zaiqi Lu , Qiang Fu

Two-photon photoacoustic tomography (TP-PAT) is a non-invasive optical molecular imaging modality that aims at inferring two-photon absorption property of heterogeneous media from photoacoustic measurements. In this work, we analyze an…

Analysis of PDEs · Mathematics 2017-05-01 Kui Ren , Rongting Zhang

We propose a microscopic theory of terahertz (THz) radiation generation on metal gratings under the action of femtosecond laser pulses. In contrast to previous models, only low-frequency currents inside the metal are considered without…

Optics · Physics 2019-08-21 Ivan Oladyshkin , Daniil Fadeev , Vyacheslav Mironov

Nonlinearity parameter tomography leads to the problem of identifying a coefficient in a nonlinear wave equation (such as the Westervelt equation) modeling ultrasound propagation. In this paper we transfer this into frequency domain, where…

Numerical Analysis · Mathematics 2023-03-31 Barbara Kaltenbacher , William Rundell

The Radon transform is a linear integral transform that mimics the data formation process in medical imaging modalities like X-ray Computerized Tomography and Positron Emission Tomography. The Hough transform is a pattern recognition…

Numerical Analysis · Mathematics 2016-05-31 Riccardo Aramini , Fabrice Delbary , Mauro C. Beltrametti , Michele Piana , Anna Maria Massone

We demonstrate results of a simulation of nonlinear reflection of intensive terahertz radiation from a silicon-on-metal metasurface involving an excitation of a high-Q trapped mode resonance. Conditions are presented to observe effects of…

Applied Physics · Physics 2019-03-15 N V Sydorchuk , S L Prosvirnin , Y Fan , F Zhang

An iterative method is derived for image reconstruction. Among other attributes, this method allows constraints unrelated to the radiation measurements to be incorporated into the reconstructed image. A comparison is made with the widely…

Computational Physics · Physics 2011-01-06 Clinton DeW. Van Siclen

Optical modulators are essential building blocks for high-capacity optical communication and massively parallel computing. Among all types of optical modulators, travelling-wave Mach-Zehnder modulators (TW-MZMs) featuring high speed and…

Optics · Physics 2025-07-14 Shuyi Li , Wei Luo , Zhenyu Li , Junqiu Liu

Terahertz scanning tunneling microscopy (THz-STM) has emerged as a potent technique for probing ultrafast nanoscale dynamics with exceptional spatiotemporal precision, whereby the acquisition of THz near-field waveforms holds paramount…

Optics · Physics 2024-03-21 Hongbo Li , Tianwu Wang , Wenyin Wei , Kai Zhang , Jing-yin Xu , Yirong Wu , Guangyou Fang
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