Camera for High-Speed THz Imaging

Zdanevičius, Justinas; Bauer, Maris; Boppel, Sebastian; Palenskis, Vilius; Lisauskas, Alvydas; Krozer, Viktor; Roskos, Hartmut G.

doi:10.1007/s10762-015-0169-1

Cited by 43 publications

(25 citation statements)

References 30 publications

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“…Apart from synthetic aperture (SA) imaging, other popular imaging methods mainly include raster scanning method [4,10] and focal plane array method [31]. Compared to a raster scanning method, no scanning motors or cumbersome reflectors are needed for SA imaging.…”

Section: Analysis and Discussionmentioning

confidence: 99%

Terahertz Wide-Angle Imaging and Analysis on Plane-wave Criteria Based on Inverse Synthetic Aperture Techniques

Gao

Qin

Deng

et al. 2016

J Infrared Milli Terahz Waves

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This paper presents two parts of work around terahertz imaging applications. The first part aims at solving the problems occurred with the increasing of the rotation angle. To compensate for the nonlinearity of terahertz radar systems, a calibration signal acquired from a bright target is always used. Generally, this compensation inserts an extra linear phase term in the intermediate frequency (IF) echo signal which is not expected in large-rotation angle imaging applications. We carried out a detailed theoretical analysis on this problem, and a minimum entropy criterion was employed to estimate and compensate for the linear-phase errors. In the second part, the effects of spherical wave on terahertz inverse synthetic aperture imaging are analyzed. Analytic criteria of plane-wave approximation were derived in the cases of different rotation angles. Experimental results of corner reflectors and an aircraft model based on a 330-GHz linear frequency-modulated continuous wave (LFMCW) radar system validated the necessity and effectiveness of the proposed compensation. By comparing the experimental images obtained under plane-wave assumption and spherical-wave correction, it also showed to be highly consistent with the analytic criteria we derived.

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Section: Analysis and Discussionmentioning

confidence: 99%

Terahertz Wide-Angle Imaging and Analysis on Plane-wave Criteria Based on Inverse Synthetic Aperture Techniques

Gao

Qin

Deng

et al. 2016

J Infrared Milli Terahz Waves

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“…Lowfrequency components at 45 Hz and their multiplicative originate from the vibration of cables induced by the cryocooler and can be strongly suppressed by using an integrated low-noise amplifier within the detector package. A considerably high channel impedance of 20 kΩ allows easy integration of low-noise amplifiers based on discrete components or integrated circuits with convenient 4-nV/ √ Hz input-referred voltage fluctuation spectral density [22], which introduces additional noise contribution only by 2.5%. The corner frequency of 1/f noise for the detector-amplifier system lies at about 30 Hz.…”

Section: A Detector Spectral Characteristicsmentioning

confidence: 99%

Field-Effect Transistor Based Detectors for Power Monitoring of THz Quantum Cascade Lasers

Zdanevičius

Cibiraite

Ikamas

et al. 2018

IEEE Trans. THz Sci. Technol.

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We report on circuit simulation, modeling, and characterization of field-effect transistor based terahertz (THz) detectors (TeraFETs) with integrated patch antennas for discrete frequencies from 1.3 to 5.7 THz. The devices have been fabricated using a standard 90-nm CMOS technology. Here, we focus in particular on a device showing the highest sensitivity to 4.75-THz radiation and its prospect to be employed for power monitoring of a THz quantum cascade laser used in a heterodyne spectrometer GREAT (German REceiver for Astronomy at Terahertz frequencies). We show that a distributed transmission line based detector model can predict the detector's performance better than a device model provided by the manufacturer. The integrated patch antenna of the TeraFET designed for 4.75 THz has an area of 13 × 13 µm 2 and a distance of 2.2 µm to the ground plane. The modeled radiation efficiency at the target frequency is 76% with a maximum directivity of 5.5, resulting in an effective area of 1750 µm 2. The detector exhibits an area-normalized minimal noise-equivalent power of 404 pW/ √ Hz and a maximum responsivity of 75 V/W. These values represent the state of the art for electronic detectors operating at room-temperature and in this frequency range.

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“…In this section, the MDP values per pixel for the MB-THz-FPAs [26,31,32,34] are compared with those of other THz detectors, such as antenna-coupled CMOS-THz-FPAs [12,13,15,16,36,44] and antenna-coupled detectors based on III-V compound semiconductor technologies [18][19][20][22][23][24] . Table 2 summarizes the parameters of these THz detectors.…”

Section: Comparison Of Performances For Different Detectorsmentioning

confidence: 99%

“…(CMOS) [12,36] 856 GHz 32x32 80 μm Goethe Univ. (CMOS) [13,44] 600 GHz 24x24 195 μm Tower Jazz (SiGe BiCMOS) [15] 315 GHz 4x4 ca. 520 μm Univ.…”

Section: Comparison Of Performances For Different Detectorsmentioning

confidence: 99%

Technology trend in real-time, uncooled image sensors for sub-THz and THz wave detection

Oda

2016

SPIE Proceedings

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The author summarizes development of uncooled microbolometer terahertz (THz) focal plane arrays (FPAs) and real-time cameras for sub-THz and THz wave detection. The array formats are 320x240 and 640x480, and the cameras have several functions, such as lock-in imaging, external-trigger imaging, image processing (pixel binning and frame integration), beam profiling and so on. The FPAs themselves are sensitive to sub-THz, THz and infrared radiations.Active imaging systems based on the imagers are described. One of them is a real-time transmission-type THz microscope which contains a THz camera and a quantum cascade laser (QCL). The other one is an active sub-THz imaging system, where a transmission imaging mode and a reflection imaging mode can be switched with one-touch operation. Strong THz emitters, such as far-infrared gas lasers and QCLs, are strongly coherent and often produce interference fringes in an image. A method of reducing the interference fringes (beam homogenizing) is described.Microbolometer FPAs developed by other groups, antenna-coupled CMOS FPA, array detectors based on GaAs high-mobility heterostructure and so on are also summarized, which operate in real-time and at room temperature. A fair method of evaluating performance of detectors with different sizes and at different wavelengths is explained and the performances of the detectors are compared.

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Camera for High-Speed THz Imaging

Cited by 43 publications

References 30 publications

Terahertz Wide-Angle Imaging and Analysis on Plane-wave Criteria Based on Inverse Synthetic Aperture Techniques

Terahertz Wide-Angle Imaging and Analysis on Plane-wave Criteria Based on Inverse Synthetic Aperture Techniques

Field-Effect Transistor Based Detectors for Power Monitoring of THz Quantum Cascade Lasers

Technology trend in real-time, uncooled image sensors for sub-THz and THz wave detection

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