Preface
The speedy development of THz science and technology bring innovation booming on the THz instruments and related applications, not only on promoting the fundamental theory and polytechnic but also on commercialization of the THz instrument products.
I am grateful to host the journal of TST as the guest editor and bring you a glance on the recent work focused on “THz instrument and applications”, including the advanced THz measure instruments come from the CETC; Hand-held miniature terahertz time-domain attenuated total reflection (ATR) spectroscopy module from Fraunhofer Institute for Industrial Mathematics ITWM, Germany, also Terahertz tomography which belong to an aspect of THz image.
At present, most of the THz instruments are still in the stage of principle research, standardized and large-scale industrial applications need to be explored urgently. The unique functions and achievements of THz instruments in the application of detection, measurement, image and so on is expected, which will definitely expand the range of its application and also improve itself. Anyway, we expect eagerly further improvements and innovations of THz instrument in the future.
Guest Editor: Fiona Zhou, from THzWave
September 30, 2019
TST, Vol. 12, No. 3, PP. 57-68
(Invited paper) Research progress of THz measurement technology based on rectangular waveguide
Fushun Nian 1*, Wanshun Jiang 2, Jianqin Deng 1, Zhuo chen 2 and Guoqing Fan 2
1 Science and Technology on Electronic Test & Measurement Laboratory, The 41st Research Institute of CETC, #98 Xiangjiang Road, Qingdao, China.
2 China Electronics Technology Instruments Co. Ltd, #98 Xiangjiang Road, Qingdao, China.
*1 Email: nfswxmnk825@163.com
(Recived September 30 2019)
Abstract: In this paper, in order to meet the testing requirements of terahertz scientific researches and engineering applications, we have introduced the relevant international standards of terahertz transmission lines, as well as the precise manufacturing and process realizations of complex three-dimensional guided wave structures such as terahertz rectangular metal waveguides, multilayer guided wave structures and double directional coupling structures. Then, the research progress on active devices and circuits such as terahertz Schottky diodes, high-efficiency frequency multiplication, harmonic mixing, power detection, etc. are presented. On the basis of the research progress, four common measuring instruments including terahertz vector network analyser, signal generator, spectrum analyser and power meter are developed. Furthermore, three measuring systems consisting of material, radar cross section (RCS) and antenna are developed. The developed measuring instruments and systems can cover the frequencies ranging from 50 GHz to 750 GHz. The whole industry chain including the core devices, components, measuring instruments and systems are independently controllable, which is able to provide a complete set of measuring solution for terahertz scientific research and engineering applications.
Keywords: Millimeter wave; Terahertz; Measuring instruments; Measuring systems.
doi: 10.11906/TST.057-068.2019.09.06
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TST, Vol. 12, No. 3, PP. 69-76
(Invited paper) Hand-held miniature terahertz time-domain attenuated total reflection spectroscopy module
Daniel Molter 1*, Garik Torosyan 2, Jens Klier 1, Carsten Matheis 1, Christian Petermann 3, Stefan Weber 1, 4, Frank Ellrich 5, Joachim Jonuscheit 1, René Beigang 4, and Georg von Freymann 1 ,4
1 Fraunhofer Institute for Industrial Mathematics ITWM, Center for Materials Characterization and Testing, 67663 Kaiserslautern, Germany
2 Photonik-Zentrum Kaiserslautern e.V., 67663 Kaiserslautern, Germany
3 TRUMPF Laser GmbH, 78713 Schramberg, Germany
4 Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
5 TH Bingen, University of Applied Sciences, 55411 Bingen
*1 Email: daniel.molter@itwm.fraunhofer.de
(Received August 30 2019 )
Abstract: We present a monolithic silicon module for time-domain attenuated total reflection spectroscopy in the terahertz spectral range. Its volume is less than 1 cm3 and is directly merged with the fiber-coupled low temperature grown gallium arsenide emitter and detector antennas. Measurements of liquids, mixtures of liquids, solutions as well as solids are presented. The compactness and direct fiber-coupling of the device makes it flexible for a variety of possible applications
Keywords: Terahertz time-domain spectroscopy, ATR
doi: 10.11906/TST.069-076.2019.09.07
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TST, Vol. 12, No. 3, PP. 77-92
(Invited paper) Terahertz tomography
Liting Niu 1, 2, Kejia Wang 1, Zhengang Yang 1, Jinsong Liu 1*
1 Huazhong University of Science and Technology, Wuhan national laboratory for optoelectronics, No. 1037 Luoyu Rd., Wuhan, Hubei, China
2 Guangdong University of Petrochemical Technology, College of Science, No.139 Guandu 2nd Rd., Maoming, Guangdong, China
*1 Email: jsliu4508@vip.sina.com
(Received September 18 2019)
Abstract: Terahertz (THz) imaging has greatly progressed over the past two decades because of the advantages of penetrativity, lower optical phantom and broadband. In this paper, we mainly introduce THz computed tomography (CT) and THz time-of-flight (TOF) imaging. Specially, the development of these two kinds of imaging techniques could be classified to some branches. One important branch is reducing the data acquisition time by 2D free-space electro-optic sampling (2D-FSEOS), asynchronous optical sampling (ASOPS) or electronically controlled optical sampling (ECOPS). Another important branch is enhancing the image resolution and quality by optimized reconstruction algorithms. The image quality also could be improved by considering Gaussian beam propagation or replacing the Gaussian beam by a zero-order Bessel beam. Moreover, application investigations of THz CT and THz TOF imaging in different fields such as art conservation, medicine detection, defect identification, industrial inspection are demonstrated and summarized.
Keywords: Terahertz spectral computed tomography, Terahertz continuous-wave computed tomography, Terahertz time-of flight imaging
doi: 10.11906/TST.077-092.2019.09.08
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