Active THz imaging and explosive detection with uncooled antenna-coupled microbolometer arrays

Meilhan, Jean–Baptiste; Dupont, Bertrand; Goudon, V.; Lasfargues, Gilles; Dera, Jerzy; Nguyen, Duy Thong; Ouvrier-Buffet, J. L.; Pocas, S.; Maillou, T.; Cathabard, O.; Barbieri, Stefano; Simoens, F.

doi:10.1117/12.883898

Cited by 16 publications

(7 citation statements)

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“…The antenna receives the electromagnetic wave and the received energy is directly coupled to the microbolometer for maximum energy collection [ 22 – 25 ]. Starting with infrared microbolometer technology, highly sensitive uncooled antenna-coupled microbolometer focal-plane arrays have been developed at CEA-Leti based on an innovative use of antennas and an optimization of resonant cavity [ 26 , 27 ]. The design of antenna-coupled microbolometer mainly aims at increasing its gain–bandwidth product and minimizing its thermal mass for fast frame rates [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Spiral Antenna-Coupled Microbridge Structures for THz Application

et al. 2017

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Bolometer sensor is a good candidate for THz imaging due to its compact system, low cost, and wideband operation. Based on infrared microbolometer structures, two kinds of antenna-coupled microbridge structures are proposed with different spiral antennas: spiral antenna on support layer and spiral antenna with extended legs. Aiming at applications in detection and imaging, simulations are carried out mainly for optimized absorption at 2.52 THz, which is the radiation frequency of far-infrared CO2 lasers. The effects of rotation angle, line width, and spacing of the spiral antenna on THz wave absorption of microbridge structures are discussed. Spiral antenna, with extended legs, is a good solution for high absorption rate at low absorption frequency and can be used as electrode lead simultaneously for simplified manufacturing process. A spiral antenna-coupled microbridge structure with an absorption rate of more than 75% at 2.52 THz is achieved by optimizing the structure parameters. This research demonstrates the use of different spiral antennas for enhanced and tunable THz absorption of microbridge structures and provides an effective way to fabricate THz microbolometer detectors with great potential in the application of real-time THz imaging.

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Section: Introductionmentioning

confidence: 99%

Spiral Antenna-Coupled Microbridge Structures for THz Application

et al. 2017

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“…The 320 × 240 array (figure 1b) is composed of 50 µm pitch pixels designed for an optimized sensitivity in the 2-4 THz range where most of the explosive fingerprints are located and QCLs are efficient [27,28]. Extensive three-dimensional finite-element method (FEM) simulations [29] were carried out with the commercial High Frequency Structure Simulator (HFSS) and Comsol codes to design two kinds of pixels.…”

Section: Prototyped Terahertz Bolometer Arraysmentioning

confidence: 99%

“…First, simple optical arrangements were tested in which samples intercept the collimated beam of a THz QCL. As shown in figure 4a,b, the 320 × 240 THz array is able to deliver real-time images of objects, respectively a scalpel blade and Leti characters written with metallic ink on paper, both concealed in a postal envelope [28]. Speckle patterns arising from the QCL source coherence degrade the image quality.…”

Section: (C) Imaging Application Demonstrationsmentioning

confidence: 99%

Terahertz real-time imaging uncooled array based on antenna- and cavity-coupled bolometers

Simoens

Meilhan

2014

Phil. Trans. R. Soc. A.

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The development of terahertz (THz) applications is slowed down by the availability of affordable, easyto-use and highly sensitive detectors. CEA-Leti took up this challenge by tailoring the mature infrared (IR) bolometer technology for optimized THz sensing. The key feature of these detectors relies on the separation between electromagnetic absorption and the thermometer. For each pixel, specific structures of antennas and a resonant quarter-wavelength cavity couple efficiently the THz radiation on a broadband range, while a central silicon microbridge bolometer resistance is read out by a complementary metal oxide semiconductor circuit. 320 × 240 pixel arrays have been designed and manufactured: a better than 30 pW power direct detection threshold per pixel has been demonstrated in the 2-4 THz range. Such performance is expected on the whole THz range by proper tailoring of the antennas while keeping the technological stack largely unchanged. This paper gives an overview of the developed bolometer-based technology. First, it describes the technology and reports the latest performance characterizations. Then imaging demonstrations are presented, such as realtime reflectance imaging of a large surface of hidden objects and THz time-domain spectroscopy beam twodimensional profiling. Finally, perspectives of camera integration for scientific and industrial applications are discussed.

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“…Additionally, many materials have high transmissivity in this frequency range. A broad range of materials, such as plastics [ 1 , 2 , 3 , 4 ], ceramics [ 5 , 6 ], illicit drugs [ 7 , 8 , 9 ], explosives [ 8 , 9 , 10 ], wood [ 11 , 12 , 13 ], paper [ 14 , 15 ], leaves [ 10 , 16 ], and blood [ 17 , 18 ] have been successfully studied with

radiation. A large number of security applications based on (sub-)THz radiation [ 8 ] have been proposed, and some are commercially available [ 8 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Real-Time High Resolution THz Imaging with a Fiber-Coupled Photo Conductive Antenna and an Uncooled Microbolometer Camera

Zolliker

Shalaby²,

Söllinger³

et al. 2021

Sensors

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We present a real-time THz imaging method using a commercial fiber-coupled photo conductive antenna as the THz source and an uncooled microbolometer camera for detection. This new combination of state-of-the-art components is very adaptable due to its compact and uncooled radiation source, whose fiber coupling allows for a flexible placement. Using a camera with high sensitivity renders real-time imaging possible. As a proof-of-concept, the beam shape of a THz Time Domain Spectrometer was measured. We demonstrate real time imaging at nine frames per second and show its potential for practical applications in transmission geometry covering both material science and security tasks. The results suggest that hidden items, complex structures and the moisture content of (biological) materials can be resolved. We discuss the limits of the current setup, possible improvements and potential (industrial) applications, and we outline the feasibility of imaging in reflection geometry or extending it to multi-spectral imaging using band pass filters.

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Active THz imaging and explosive detection with uncooled antenna-coupled microbolometer arrays

Cited by 16 publications

References 0 publications

Spiral Antenna-Coupled Microbridge Structures for THz Application

Spiral Antenna-Coupled Microbridge Structures for THz Application

Terahertz real-time imaging uncooled array based on antenna- and cavity-coupled bolometers

Real-Time High Resolution THz Imaging with a Fiber-Coupled Photo Conductive Antenna and an Uncooled Microbolometer Camera

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