Passive 350 GHz Video Imaging Systems for Security Applications

Heinz, Erik; May, T.; Born, D.; Zieger, Gabriel; Anders, S.; Zakosarenko, V.; Meyer, H.‐G.; Schäffel, Christoph

doi:10.1007/s10762-015-0170-8

Cited by 52 publications

(21 citation statements)

References 32 publications

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“…This bands are of particular interest for stand-off imaging that can be achieved either by passive imaging system [13] that require cryogenic detectors or active imaging scheme [14] by illumination of the target and detection with uncooled devices. Depending on the application one will favor higher frequencies windows in order to improve imaging resolution, at the cost of a lower screening range due to increased attenuation of residual water vapor with frequency.…”

Section: Description Of the Optical Systemmentioning

confidence: 99%

Performance evaluation of active sub-Terahertz systems in Degraded Visual Environments (DVE)

et al. 2016

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This paper addresses the problem of critical operations in Degraded Visual Environment (DVE). DVE usually refer when the perception of a pilot is degraded by environmental factors, including the presence of obscurants from bad weather (e.g. fog, rain, snow) or accidental events (e.g. brownout, whiteout, smoke). Critical operations in DVE are a growing field of research as it is a cause of numerous fatal accidents for operational forces. Due to the lack of efficient sources and sensors in the Terahertz (THz) region, this domain has remained an unexplored part of the electromagnetic spectrum. Recently, the potential use of sub-Terahertz waves has been proposed to see through dense clouds of obscurants (e.g. sand, smoke) in DVE conditions. In order to conduct a performance evaluation of sub-Terahertz systems, several sub-terahertz systems (e.g. bolometer-array cameras, liquid helium cooled bolometers) were operated in artificial controlled DVE conditions at ONERA facilities. The purpose of this paper is to report field experiments results in controlled DVE conditions: attenuation measurements from 400 GHz to 700 GHz with a performance evaluation of different sub-Terahertz systems are presented.

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Section: Description Of the Optical Systemmentioning

confidence: 99%

Performance evaluation of active sub-Terahertz systems in Degraded Visual Environments (DVE)

et al. 2016

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“…Since coming to the attention of the scientific community, terahertz technology has made a series of breakthroughs due to its outstanding intrinsic advantages . With the rapid development of terahertz applications in fields such as terahertz communication, terahertz signal modulation, terahertz imaging, terahertz detection, and so on, terahertz related circuits and electronic components have been widely applied to current technologies. The fast‐growing applications for terahertz waves have led to an urgent demand for terahertz shielding materials in order to effectively reduce the interference of terahertz wave signals, improve their transmission environment, and ensure that the delicate electronic instruments work as normal.…”

Section: Introductionmentioning

confidence: 99%

Graphene‐Based Composites Combining Both Excellent Terahertz Shielding and Stealth Performance

Huang

Chen

et al. 2018

Advanced Optical Materials

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terahertz imaging, [9][10][11] terahertz detection, [12][13][14] and so on, terahertz related circuits and electronic components have been widely applied to current technologies. The fast-growing applications for terahertz waves have led to an urgent demand for terahertz shielding materials in order to effectively reduce the interference of terahertz wave signals, improve their transmission environment, and ensure that the delicate electronic instruments work as normal. Moreover, terahertz stealth materials also play a very important role in the fields of national security and information protection, which may help to avoid significant losses to individuals, enterprises, and even countries. Therefore, high-performance terahertz shielding/stealth materials have the potential for wide applications. [15] Traditional terahertz shielding materials are mainly composed of reflective materials because they reflect the incident terahertz wave by simply increasing conductivity. [16,17] For example, it is reported that a terahertz-shielding membrane prepared by a pyrolysis process for commercial polyimide has a very high reflectivity of more than 90%. [18] However, reflective shielding materials have two fatal flaws. First, reflective shielding materials cannot completely eliminate the interference of terahertz waves, because the reflected terahertz wave still adversely affects other sophisticated electronic elements inside the shielded devices. [19] Second, reflective shielding materials usually have a large density. The reflective Strong terahertz-response material which exhibits both excellent terahertz shielding and stealth performance is promising in practical applications of terahertz technology. Here, ultralight graphene foam (GF) and multiwalled carbon nanotubes/multiwalled graphene foam (MGF) have been first demonstrated to achieve both superior terahertz shielding and stealth performance due to the dominant absorption loss with negligible reflection. The terahertz shielding effectiveness values of GF and MGF, both 3 mm thick, reach up to 74 and 61 dB. Meanwhile, their average terahertz reflection loss values are achieved up to 23 and 30 dB, respectively, which are the best results in existing broadband terahertz shielding/stealth materials. Importantly, their qualified absorption bandwidths (reflection loss value larger than 10 dB) cover the entire measured frequency band of 0.1-1.6 THz. Furthermore, the quantitative relationships between the terahertz shielding effectiveness, reflection loss, and material parameters are accurately established, which should facilitate the material design for terahertz shielding and stealth. Comprehensively considering the important indicators of density, bandwidth, and intensity, the specific average terahertz shielding coefficient and the specific average terahertz absorption performance are achieved up to 1.1 × 10 5 and 3.6 × 10 4 dB cm 3 g −1 , respectively, which is over thousands of times larger than other kinds of materials reported previously. Shielding/Stealth MaterialsThe...

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“…Therefore, a number of THz stand-off imaging systems have been developed by several research groups. These are either active systems, relying on artificial THz illumination with a narrow-band THz source [4] or passive systems, which are in some sense the THz analogue to infrared cameras since these systems detect the natural THz radiation emitted or reflected from a person or object [5]. Both imaging approaches have a low number of detectors -typically one for active imagers and up to about 100 for passive imagers.…”

Section: Introductionmentioning

confidence: 99%

Terahertz Dynamic Aperture Imaging at Standoff Distances Using a Compressed Sensing Protocol

Augustin¹,

Jung²,

Frohmann³

et al. 2019

IEEE Trans. THz Sci. Technol.

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In this text, results of a 0.35 terahertz (THz) dynamic aperture imaging approach are presented. The experiments use an optical modulation approach and a single pixel detector at a stand-off imaging distance of ≈1 m. The optical modulation creates dynamic apertures of 5 cm diameter with ≈2000 individually controllable elements. An optical modulation approach is used here for the first time at a large far-field distance, for the investigation of various test targets in a fieldof-view of 8 x 8 cm. The results highlight the versatility of this modulation technique and show that this imaging paradigm is applicable even at large far-field distances. It proves the feasibility of this imaging approach for potential applications like stand-off security imaging or far field THz microscopy.

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Passive 350 GHz Video Imaging Systems for Security Applications

Cited by 52 publications

References 32 publications

Performance evaluation of active sub-Terahertz systems in Degraded Visual Environments (DVE)

Performance evaluation of active sub-Terahertz systems in Degraded Visual Environments (DVE)

Graphene‐Based Composites Combining Both Excellent Terahertz Shielding and Stealth Performance

Terahertz Dynamic Aperture Imaging at Standoff Distances Using a Compressed Sensing Protocol

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