Source: http://isp.kiev.ua/index.php/en/thz-sensors-project
Timestamp: 2019-04-20 10:49:37+00:00

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You are here: Home NATO SfP "Uncooled-THz"
NATO SfP Project 984544 "Uncooled-THz"
The general objective of this project is to develop a new uncooled- or moderately cooled- (T≥80 K) bolometer that responds quickly (with a response time τ less than 50 ns), thereby to directly detect terahertz (THz) radiation. This detector will use a sensitive element made from the narrow-gap semiconductor Hg1-xCdxTe (MCT) / Cd1-xZnxTe (CZT) material. It can be assembled into arrays. These arrays, integrated with modern readout circuits, will be applied to assure the availability of a new generation of real-time vision systems for security applications in detecting explosives in the THz/mm wave-window. Working at room temperature, or moderately cooled, the system will locate and image dangerous organic components, drugs, and hidden objects that are either absorbing or reflecting in the THz/mm radiation region.
The key novelty of this project lies in development of a MCT/CZT prototype detector, based on a new physical principle for narrow-gap semiconductors, namely, the free-carrier heating in MBE- or LPE-structured MCT as the THz detector layer. Different solutions will be considered to assure the maximum sensitivity of the detector element, for example: a) A hot-electron bolometer; b) Detectors on the basis of incorporating MCT with a built-in p-n junction; and, c) Detectors based on the MCT quantum wells. This project is underpinned by automatically measuring and testing developed THz arrays of detectors, and study and characterization of the manufactured MCT/CZT structures.
The project implies our concurrent optimization of the antenna-detector’s coupling, the development and manufacture of advanced components, and upgrading the flip-chip aligner-bonder machine in compliance with requirements of the technology needed for assembling the THz sensor.
Vacuum equipment with the magnetron module for coating of metal contacts "WUP-5M"
There was presented the report #MTE-5: “Modeling of Printed Antennas on Electrically Thick Subtrate for THz Focal Plane Array” by Mykola Sakhno, J. Gumenjuk-Sichevska, F. Sizov.
Mykola Sakhno, who presented this work, received first place in the section "MICROWAVE & TERAHERTZ ELECTRONICS"
“MCT as sub-terahertz and infrared detector” by Fiodor F. Sizov, Vyacheslav V. Zabudsky, Sergey A. Dvoretsky, Vladimir A. Petryiakov, Aleksandr G. Golenkov, Katerina V. Andreyeva, Zinoviia F. Tsybrii, Anna V. Shevchik-Shekera, Ernesto Dieguez.
Report abstract: Development of infrared and sub-terahertz radiation detectors at the same sensitive elements on the base of mercury-cadmium-telluride (MCT) is reported. Two-color un-cooled and cooled to 78 K narrow-gap MCT semiconductor thin layers, grown by liquid phase epitaxy or molecular beam epitaxy method on high resistivity CdZnTe or GaAs substrates, with bow-type antennas were considered both as sub-terahertz direct detection bolometers and 3 to 10 mkm infrared photoconductors. Their room temperature noise equivalent power (NEP) at frequency ~ 140 GHz and signal-to-noise ratio (S/N) in the spectral sensitivity maximum under the monochromatic (spectral resolution of ~0.1 mkm) globar illumination were reached NEP ~4.5*10-10 W/Hz1/2 and S/N~50, respectively.
“Mercury-Cadmium-Telluride thin layers as sub-THz and IR detectors” by F. Sizov, V. Zabudsky, S. Dvoretskii, V. Petryakov, O. Golenkov, Z. Tsybrii, E. Dieguez, E. Repiso.
Report abstract:: Bi-color un-cooled and cooled to 78 K narrow-gap mercury-cadmium-telluride (MCT) semiconductor thin layers with antennas were considered both as sub-terahertz (sub-THz) direct detection bolometers, and 3 to 10 mkm infrared (IR) photoconductors. Noise equivalent power (NEP) of MCT sub-THz detectors at frequency ~ 140 GHz was estimated as well as its IR response at T = 78 K and 300 K. The characteristics of such bi-color detectors can be controlled and improved by selection of parameters of initial layers and of the antennas configuration. Download full report.
Sakhno Mykola, PhD student of 38 department was awarded the second Prize of European Microwave Association (EuMA). The team of the department congratulates Mykola with bright scientific achievement and wishes him further achievements and accomplishments!
by using Shimadzu UV-3600 two-beam spectrophotometer.
To apply MCT layers in sub-THz regions, the detectors with the active area of ~50x25 mkm in size were prepared. The rectangular form of sensitive elements was chosen for increasing the detector resistance of the active area to approach the antenna impedance Z to the values 100…200 Ohm for a bow-tie antenna.
For the sub-THz/THz radiation energy transfer into active area, the antennas with dimensions about the wavelength are used. The design of the detector was improved, as compared with that earlier developed, so that electric contacts were formed outside the antenna to avoid their influence on the detected signal.
Electronic circuit for controlling the current (voltage) bias and preliminary signal amplification from the linear arrays was developed. The multichannel system for preliminary signal treatment from the linear arrays was fabricated (Fig. 11). Here the scheme conditionally divided in two parts. The first part specifies the stabilized current for the heating of MCT bolometers. The second part serves as amplifier of the output signal from a bolometer. For obtaining the same signals at the output of receivers the gain of amplifier is controlled.
To obtain the image using THz detectors linear arrays, it is important to create an optical system, which allows the focusing of THz radiation into each detector simultaneously. This configuration of optical system reduces the scanning time. For this aim we modelled and manufactured such system which consists of two parts. The first part includes the pair of lenses that focus the radiation on the object, the second ones - on THz detectors. We used for the first pair of lenses spherical and cylindrical ones for obtaining THz radiation distribution in the line. Efficiency of this type of lenses was tested on set-up presented in Fig. 1. The scheme consists of a sub-THz source, lenses, MCT sub-THz detectors, registration system and computer with software.
Fig. 1. Photo of set-up for pair of spherical and cylindrical lenses testing.
The sub-THz source was used as the emitter that generates a continuous, linearly polarized, essentially monochromatic wave at 140 GHz. This scheme was chosen as an intermediate for scanning simulating the illumination in the plane of installation of object.
Manufactured cylindrical lens and spot diagram, created by passing a sub-THz beam through the pair of spherical and cylindrical lenses are presented in Fig. 2-3, respectively. A lens spot diagram is the best overall evaluation for a quick check of image quality. Aspects such as astigmatism, coma, spherical aberration, chromatic aberration and more can be viewed instantly.
Fig. 2. Photo of the lens, made on a computer-controlled lathe. Lens material was PTFE.
Fig. 2. Photo of the lens, made with using 3D print. Lens material was ABS.
For all of the lenses presented here, we have chosen a focal length of 25 mm and a diameter of 60 mm, therefore the numerical aperture was 1.2 for all lenses (NA = d/(2 f)). These lenses have unique profile which eliminates monochromatic aberrations. All of the lenses were tested on the manufactured set-up and showed satisfactory quality for THz imaging system. 3D print of the THz lenses has perspective for their using in THz vision systems.
F. Sizov, V. Zabudsky, S. Dvoretskii, V. Petryakov, O. Golenkov, K. Andreyeva, Z. Tsybrii. Two-color detector: Mercury-Cadmium-Telluride as a terahertz and infrared detector, Applied Physics Letters, 106, p. 082104-1 – 182104-4 (2015); doi: 10.1063/1.4913590.
Fiodor F. Sizov, Vyacheslav V. Zabudsky, Sergey A. Dvoretsky, Vladimir A. Petryiakov, Aleksandr G. Golenkov, Katerina V. Andreyeva, Zinoviia F. Tsybrii, Anna V. Shevchik-Shekera, Ernesto Dieguez. MCT as sub-terahertz and infrared detector, Proc. SPIE 9483, Terahertz Physics, Devices, and Systems IX: Advanced Applications in Industry and Defense, 94830V (May 13, 2015); doi: 10.1117/12.2176854.
F. Sizov,1V. Zabudsky, S. Dvoretskii, V. Petryakov, O. Golenkov, Z. Tsybrii, E. Dieguez, E. Repiso. Mercury-Cadmium-Telluride thin layers as sub-THz and IR detectors, 8th THz Days - - 31 March – 2 April 2015, Areches, France, p. 135.
Fiodor F. Sizov, Vyacheslav V. Zabudsky, Sergey A. Dvoretsky, Vladimir A. Petryiakov, Aleksandr G. Golenkov, Katerina V. Andreyeva, Zinoviia F. Tsybrii, Anna V. Shevchik-Shekera, Ernesto Dieguez. MCT as sub-terahertz and infrared detector, SPIE DSS Conference 9483: Terahertz Physics, Devices, and Systems IX: Advanced Applications in Industry and Defense, 20-24 April 2015, Baltimore, USA, p. 310.
Fedir Sizov, Zinoviia Tsybrii, Vyacheslav Zabudsky, Oleksandr Golenkov, Volodymyr Petryakov, Sergei Dvoretskii. MCT thin layers as sub-terahertz and infrared bi-color detector, Int. Scient. And tech. conf. “Laser technologies. Lasers and their application”, 17-19 June 2015, Truskavets, Ukraine, p.98-100.

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