NDT

Terahertz is a powerful technique allowing non destructive test of composite materials. Both time and frequency domain, pulsed and FMCW can be used to inspect composite materials from the aeronautics industry. Several defects like crack, insertions or debonds can be revealed.

Continuous‐wave scanning terahertz near‐field microscope

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Terahertz research image associated with Continuous-wave scanning terahertz near-field microscope

The work reported by Guillet, Chusseau, Adam, Grosjean, Penarier, Baida and Charraut describes the development of a continuous‑wave terahertz (THz) near‑field microscope that exploits Sommerfeld surface waves guided along metallic wires. By combining differential phase plates, a Y‑splitter and a…

Theoretical and experimental studies of metallic grids absorption: Application to the design of a bolometer

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Research figure associated with Room temperature thermopile THz sensor

The study delivers a comprehensive, validated framework for designing metallic grid absorbers with precisely tailored electrical resistivity, enabling the creation of efficient, room‑temperature bolometers and other thermal detectors. By treating structured metal layers as equivalent homogeneous…

Linear to radial polarization conversion in the THz domain using a passive system

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Terahertz research image associated with Continuous-wave scanning terahertz near-field microscope

The work presents a compact, passive device that transforms a conventional linearly polarized terahertz (THz) beam into a radially polarized one, a field configuration that offers superior focusing, enhanced longitudinal fields, and improved coupling to near‑field probes. By adapting a proven…

Propagation beam consideration for 3D THz computed tomography

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Research figure associated with Propagation beam consideration for 3D THz computed tomography

The study introduces a new physical model that captures the real behaviour of terahertz (THz) radiation when used for three-dimensional tomographic imaging. Unlike conventional X‑ray methods that treat the beam as a straight, uniform ray, the authors model the THz pulse as a Gaussian beam whose…

Near-field wire-based passive probe antenna for the selective detection of the longitudinal electric field at terahertz frequencies

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Terahertz research image associated with Continuous-wave scanning terahertz near-field microscope

The work presents a novel passive probe antenna that can be operated at terahertz (0.1 THz) frequencies using a simple, purely passive structure. The antenna consists of a slender metal wire backed by a discontinuous phase plate that converts an ordinary linearly‑polarized free‑space beam into a…

Aeronautics composite material inspection with a terahertz time-domain spectroscopy system

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Terahertz research image associated with Terahertz waves for contactless control and imaging in aeronautics industry

An in-depth editorial guide to Aeronautics composite material inspection with a terahertz time-domain spectroscopy system, its scientific context, terahertz contribution, applications, and collaboration potential in Non-Destructive Testing.

Low-frequency noise effect on terahertz tomography using thermal detectors

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Terahertz research image associated with Low-frequency noise effect on terahertz tomography using thermal detectors

Terahertz computed tomography (THz‑CT) offers a powerful, non‑contact imaging modality for security screening, material inspection and biomedical diagnostics, yet its practical deployment has been limited by the low photon energy of terahertz waves and the high noise levels inherent to thermal…

Room temperature thermopile THz sensor

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Research figure associated with Room temperature thermopile THz sensor

Executive Summary The research presented here delivers a novel room‑temperature terahertz (THz) sensor that converts incident electromagnetic power into a measurable electrical signal via a thermopile assembled on a micro‑fabricated silicon dioxide membrane. By using a metallic grid absorber…

Room temperature Si–Ti thermopile THz sensor

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Research figure associated with Room temperature thermopile THz sensor

The work presents a room‑temperature terahertz (THz) detector based on a thermopile that converts absorbed THz radiation into a measurable voltage. The sensor’s absorber is a metallic grid engineered through a multilayer theoretical model that accounts for diffraction and equivalent resistivity,…

A comprehensive study of the application of the EOP techniques on bipolar devices

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Research figure associated with Room temperature thermopile THz sensor

The study demonstrates that Electro‑Optical Probing (EOP), a non‑invasive laser‑based diagnostic technique, can be reliably applied to bipolar semiconductor devices to uncover internal electrical activity and identify failure mechanisms that are otherwise invisible to conventional analysis. By…

Ordered subsets convex algorithm for 3D terahertz transmission tomography

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Terahertz research image associated with Ordered subsets convex algorithm for 3D terahertz transmission tomography

This research introduces a practical, high‑performance technique for three‑dimensional terahertz (THz) tomography that is designed to meet the stringent demands of non‑destructive inspection in industrial and cultural heritage contexts. The method refines the maximum‑likelihood reconstruction…

Shape-from-focus for real-time terahertz 3D imaging

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Terahertz research image associated with Shape-from-focus for real-time terahertz 3D imaging

The study demonstrates that the Shape‑from‑Focus (SFF) algorithm, traditionally used in optical microscopy, can be successfully applied to real‑time terahertz (THz) imaging systems to generate sharp two‑dimensional images and depth maps of thin or layered objects. By recording a rapid stack of…

Advanced Processing Sequence for 3-D THz Imaging

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Terahertz research image associated with Ordered subsets convex algorithm for 3D terahertz transmission tomography

The authors present a comprehensive, automated image‑processing pipeline that transforms raw terahertz (THz) radiographs into detailed three‑dimensional reconstructions of an object’s internal structure. The sequence combines a regularized tomographic reconstruction algorithm with K‑means…

Terahertz imaging and tomography as efficient instruments for testing polymer additive manufacturing objects

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Terahertz research image associated with Terahertz Nondestructive Testing with Ultra-Wideband FMCW Radar

Terahertz (THz) imaging and tomography have been shown to provide a rapid, non‑destructive and radiation‑free method for inspecting polymer parts produced by additive manufacturing. Unlike conventional X‑ray tomography, THz techniques offer the possibility of routine quality assurance for complex…

Liquid index matching for 2D and 3D terahertz imaging

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Research figure associated with Propagation beam consideration for 3D THz computed tomography

Terahertz (THz) imaging offers a non‑destructive, contactless method for probing the internal structure of dielectric materials, yet its practical use has been limited by severe artifacts caused by refractive‑index mismatch at sample interfaces. This study demonstrates that immersing non‑planar…

Art Painting Diagnostic Before Restoration with Terahertz and Millimeter Waves

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Terahertz research image associated with TeraPulse Lx for terahertz imaging of painting on canvas

An in-depth editorial guide to Art Painting Diagnostic Before Restoration with Terahertz and Millimeter Waves, its scientific context, terahertz contribution, applications, and collaboration potential in Biomedical Imaging.

Terahertz frequency modulated continuous wave imaging advanced data processing for art painting analysis

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Terahertz research image associated with Guided Reflectometry Imaging Unit Using Millimeter Wave FMCW Radars

An in-depth editorial guide to Terahertz frequency modulated continuous wave imaging advanced data processing for art painting analysis, its scientific context, terahertz contribution, applications, and collaboration potential in Art & Cultural Heritage.

NearSense – Advances Towards a Silicon-Based Terahertz Near-Field Imaging Sensor for Ex Vivo Breast Tumour Identification

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Research figure associated with Terahertz refractive index-based morphological dilation for breast carcinoma delineation

An in-depth editorial guide to NearSense – Advances Towards a Silicon-Based Terahertz Near-Field Imaging Sensor for Ex Vivo Breast Tumour Identification, its scientific context, terahertz contribution, applications, and collaboration potential in Biomedical Imaging.

Pilot study of freshly excised breast tissue response in the 300 – 600 GHz range

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Research figure associated with Terahertz refractive index-based morphological dilation for breast carcinoma delineation

The pilot research demonstrates that terahertz (THz) imaging in the 300‑600 GHz band can reliably distinguish between malignant and healthy breast tissues within freshly excised specimens. Because the refractive index of cancerous tissue mixtures is measurably higher than that of fat or normal…

Terahertz Spectroscopy and Quantum Mechanical Simulations of Crystalline Copper-Containing Historical Pigments

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Terahertz research image associated with Terahertz spectroscopy and quantum mechanical simulations of crystalline copper-containing historical pigments

The study demonstrates how terahertz (THz) spectroscopy, when coupled with solid‑state density functional theory (ss‑DFT) simulations, provides a powerful, non‑destructive tool for the identification and analysis of copper‑containing historical pigments used in art, manuscripts, and cultural…

Scanning laser terahertz near-field reflection imaging system

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Terahertz research image associated with Continuous-wave scanning terahertz near-field microscope

A new terahertz imaging platform has been introduced that reconciles the high sensitivity of terahertz (THz) radiation with the practical constraints of industrial and medical diagnostics. By focusing femtosecond pulses from a fiber‑coupled 1.56 µm laser onto a thin gallium arsenide crystal, the…

Iterative Tree Algorithm to Evaluate Terahertz Signal Contribution of Specific Optical Paths Within Multilayered Materials

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Terahertz research image associated with Guided Reflectometry Imaging Unit Using Millimeter Wave FMCW Radars

Terahertz time‑domain spectroscopy (THz‑TDS) is a powerful, contact‑less technique for probing the internal structure of layered materials, a capability that is increasingly valuable in aerospace, automotive, composite manufacturing, and cultural heritage conservation. Conventional THz‑TDS analysis…

Fast Terahertz Spectroscopic Holographic Assessment of Optical Properties of Diabetic Blood Plasma

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Terahertz research image associated with Fast terahertz spectroscopic holographic assessment of optical properties of diabetic blood plasma

The research presents a novel, rapid diagnostic technique that harnesses terahertz (THz) pulse time‑domain holography to evaluate the optical properties of lyophilized blood plasma pellets. By converting plasma into compact, freeze‑dried tablets, the method overcomes the limitations of liquid blood…

Terahertz phase retrieval imaging in reflection

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Terahertz research image associated with Terahertz phase retrieval imaging in reflection

The work demonstrates, for the first time, a practical, single‑beam terahertz (THz) phase‑retrieval imaging system that operates in a reflection configuration at a continuous‑wave frequency of 0.287 THz. By recording the reflected intensity at 27 axial positions and combining the signals from two…

Guided terahertz pulse reflectometry with double photoconductive antenna

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Terahertz research image associated with Guided terahertz pulse reflectometry with double photoconductive antenna

The research team from Bordeaux and Limoges has engineered a compact, optics‑free terahertz imaging system that delivers high‑resolution reflectometry through a single hollow‑core waveguide. By integrating two photoconductive antennas on a single low‑temperature gallium arsenide chip and coupling…

A Versatile Illumination System for Real-Time Terahertz Imaging

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Terahertz research image associated with Skeletonization and 3D rendering with real time terahertz tomography

Terahertz (THz) technology has long been recognised for its unique ability to penetrate non‑conductive, often opaque materials and reveal hidden structures without causing damage. Yet the potential of THz imaging for rapid, on‑line non‑destructive testing (NDT) and quality control has remained…

Characterization of Varnish Ageing and its Consequences on Terahertz Imagery: Demonstration on a Painting Presumed of the French Renaissance

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Terahertz research image associated with TeraPulse Lx for terahertz imaging of painting on canvas

Terahertz (THz) imaging has been demonstrated as a powerful, non‑contact, non‑ionizing technique for probing the internal structure of cultural heritage objects, particularly those mounted on metal supports where conventional optical, X‑ray, or infrared methods fail. In this study, a…

Terahertz near-field microscopy of ductal carcinoma in situ (DCIS) of the breast

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Research figure associated with Scanning point terahertz source microscopy of unstained comedo ductal carcinoma in situ

Executive Summary Recent research has demonstrated that terahertz (THz) near‑field microscopy can be employed to detect ductal carcinoma in situ (DCIS) – a pre‑invasive breast cancer that is notoriously difficult to identify during surgery due to its small size (50–500 µm). Conventional THz…

Guided Reflectometry Imaging Unit Using Millimeter Wave FMCW Radars

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Terahertz research image associated with Guided Reflectometry Imaging Unit Using Millimeter Wave FMCW Radars

The study demonstrates a new generation of terahertz‑frequency radar probes that combine a frequency‑modulated continuous‑wave (FMCW) transmitter with a thin‑wall hollow‑core dielectric waveguide. By guiding the millimetre‑wave signal directly inside a polymer pipe, the device eliminates the need…

Terahertz refractive index-based morphological dilation for breast carcinoma delineation

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Research figure associated with Terahertz refractive index-based morphological dilation for breast carcinoma delineation

Terahertz time‑domain imaging has been harnessed to generate refractive‑index maps of freshly excised breast tissue, enabling a non‑ionising, optical‑based assessment of tumour margins during breast‑conserving surgery. By converting the refractive‑index distribution into a binary map and then…

TeraPulse Lx for terahertz imaging of painting on canvas

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Terahertz research image associated with TeraPulse Lx for terahertz imaging of painting on canvas

An in-depth editorial guide to TeraPulse Lx for terahertz imaging of painting on canvas, its scientific context, terahertz contribution, applications, and collaboration potential in Art & Cultural Heritage.

Label-Free Observation of Micrometric Inhomogeneity of Human Breast Cancer Cell Density Using Terahertz Near-Field Microscopy

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Terahertz research image associated with Label-Free Observation of Micrometric Inhomogeneity of Human Breast Cancer Cell Density Using Terahertz Near-Field Microscopy

Terahertz near‑field microscopy built around a scanning point terahertz source (SPoTS) achieves a spatial resolution of approximately ten micrometres, breaking the diffraction‑limited barrier that has traditionally constrained terahertz imaging to millimetre scales. By placing a formalin‑fixed,…

Terahertz waves for contactless control and imaging in aeronautics industry

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Terahertz research image associated with Terahertz waves for contactless control and imaging in aeronautics industry

Terahertz technology is emerging as a powerful, contact‑free tool for the aeronautics sector, offering both rapid structural health monitoring and precise material characterization. The study demonstrates that frequency‑modulated continuous‑wave (FMCW) radars operating in the 100–300 GHz band can…

Single-scan multiplane phase retrieval with a radiation of terahertz quantum cascade laser

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Research figure associated with An algorithm of unordered wavefront propagation in terahertz phase retrieval with dense multiplane data acquisition

An in-depth editorial guide to Single-scan multiplane phase retrieval with a radiation of terahertz quantum cascade laser, its scientific context, terahertz contribution, applications, and collaboration potential in Biomedical Imaging.

Skeletonization and 3D rendering with real time terahertz tomography

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Terahertz research image associated with Skeletonization and 3D rendering with real time terahertz tomography

The study demonstrates a fully integrated, real‑time terahertz computed tomography platform that can acquire full‑field images at 25 frames per second, reconstruct a three‑dimensional volume, and automatically process that data to reveal detailed internal morphology within a single minute. By…

Terahertz Nondestructive Testing with Ultra-Wideband FMCW Radar

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Terahertz research image associated with Terahertz Nondestructive Testing with Ultra-Wideband FMCW Radar

The 150 GHz continuous‑wave radar, based on a homodyne eight‑harmonic mixing architecture, delivers non‑contact, high‑dynamic‑range imaging of a broad class of materials at sub‑millimetre depth resolution and up to 7.6 kHz frame rates. Achieving a 100 dB measurement dynamic range for few‑second…

Scanning point terahertz source microscopy of unstained comedo ductal carcinoma in situ

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Research figure associated with Scanning point terahertz source microscopy of unstained comedo ductal carcinoma in situ

Executive Summary Terahertz (THz) imaging has long promised a label‑free path to diagnosing cancers by exploiting the sensitivity of THz waves to tissue hydration, cellular density, and molecular composition. In breast cancer, the earliest precursor lesion—ductal carcinoma in situ (DCIS)—requires…

Terahertz diffractive imaging with saturated data inpainting

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Terahertz research image associated with Terahertz Diffractive Imaging with Saturated Data Inpainting

Executive Summary This research introduces a novel algorithm—Multiplane Iterative Phase Retrieval with Inpainting (SBMIR‑I)—that corrects for over‑exposure in terahertz (THz) diffraction imaging. By automatically “inpainting” saturated regions in the measured intensity data, the algorithm…

Feasibility of Using a 300 GHz Radar to Detect Fractures and Lithological Changes in Rocks

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Terahertz research image associated with Feasibility of Using a 300 GHz Radar to Detect Fractures and Lithological Changes in Rocks

The study demonstrates that a compact, frequency‑modulated continuous‑wave radar operating at 300 GHz can non‑destructively image rock interiors with unprecedented detail. By scanning a 121 cm² area in only fifteen minutes, the system resolves millimetre‑scale fractures and subtle lithological…

An algorithm of unordered wavefront propagation in terahertz phase retrieval with dense multiplane data acquisition

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Research figure associated with An algorithm of unordered wavefront propagation in terahertz phase retrieval with dense multiplane data acquisition

An in-depth editorial guide to An algorithm of unordered wavefront propagation in terahertz phase retrieval with dense multiplane data acquisition, its scientific context, terahertz contribution, applications, and collaboration potential in Biomedical Imaging.

Augmented Reality Terahertz (AR-THz) Sensing and Imaging with Frequency-Modulated Continuous-Wave Radar

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Terahertz research image associated with Augmented reality terahertz (AR-THz) sensing and imaging with frequency-modulated continuous-wave radar

The research introduces a handheld terahertz (THz) sensing platform that fuses a frequency-modulated continuous wave (FMCW) radar with a smartphone‑based augmented reality (AR) interface. The integration eliminates the need for heavy mechanical scanners, reducing system weight and cost while…

Broadband THz emission of long pulses from photomixing process with optical chirped pulses

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Terahertz research image associated with Guided terahertz pulse reflectometry with double photoconductive antenna

The study introduces a novel photomixing technique that generates long terahertz (THz) pulses with a broad, linearly chirped spectrum by interfering two optical pulses of opposite chirp. By stretching each pulse to roughly 90 ps and applying opposite frequency sweeps, the beat frequency evolves…

SubTHz Fully-Metallic Geodesic Luneburg Lens Antenna

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Research figure associated with SubTHz Fully-Metallic Geodesic Luneburg Lens Antenna

Executive Summary A team of researchers from KTH Royal Institute of Technology, INSA Rennes, the University of Bordeaux, and ESA has developed and experimentally validated a fully metallic geodesic Luneburg lens antenna that operates in the sub‑terahertz (sub‑THz) frequency band between 128 and 132…

Feasibility of Using a 300 GHz Radar to Detect Fractures and Lithological Changes in Rocks

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FMCW radar rock non destructive testing

This article examines the possibility of using a high frequency radar (300 GHz) to detect fractures and lithological changes in rocks. This study, carried out in collaboration between Federico Sanjuan (University of Pau, France) and the IMS laboratory (University of Bordeaux), is in the context of the improvement of the methods of detection and quantification … Read more

Guided Reflectometry Imaging Unit using Millimeter Wave FMCW Radars

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Plastic wavguide for terahertz sensing in reflection

In this paper published in july 2020 in IEEE Transactions on Terahertz Science and Technology, we present a reflectometry sensing system associated with a frequency modulated continuous wave radar. Then, a solid immersion lens is added to the system to improve the resolution. Abstract of terahertz reflectometry setup Frequency Modulated Continuous Wave (FMCW) radar systems … Read more

Processing sequence for non-destructive inspection based on 3D terahertz images

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In this paper, a processing sequence has been developed to achieve automated analysis and measurements from 3D terahertz acquisitions. This sequence first performs a tomographic reconstruction from a 3D acquisition made by a continuous millimetre wave system. This reconstruction is based on the Ordered Subsets Convex (OSC) algorithm and has been optimized for 3D THz tomography. Optimisations consist of i) including the Gaussian beam model in the computation of expected measured intensity, ii) modelling the blank scan and dark-field from measurements and, iii) taking account for these models in the algorithm. The new method, called THz-OSC, outperforms both the BFP and THz-SART reconstructions.

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