TST, Vol. 12, No. 1, PP. 1-11
(Invited paper) Terahertz in-vivo studies: improving experimental techniques to eliminate variables
Rayko Ivanov Stantchev 1, Qiushuo Sun 1, Shuting Fan 2, Xuequan Chen 1, and Emma Pickwell-MacPherson 1, 3*
1 Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong
2 College of Electronic Science and Technology, Shenzhen University, 3688 Nanhai Rd, Shenzhen, Guangdong, China 518060
3 Department of Physics, Warwick University, Coventry, UK
* Email: e.pickwell.97@cantab.net
(Recived Auguest 31, 2018)
Abstract: THz spectroscopic imaging is highly sensitive to water content, and as abnormal water content is usually indicative of afflictions THz imaging has great medical potential in early-stage disease diagnosis. However, clinical use requires fast acquisition, repeatability and cost-effective, reliable equipment, which is not yet offered by THz technology. In this work we have reviewed the methods and technologies that have the potential of allowing the transference of THz from the laboratory to the hospital. First, we discuss the need for reliable sample characterization and the calibration methods that overcome the relevant problems. Second, we discuss the usefulness of THz in disease diagnosis and further outline how occlusion of the skin must be accounted for accurate diagnosis. Thirdly, we discuss how adaptive sampling and smart image under-sampling can be used to reduce measurement times.
Keywords: Terahertz spectroscopy, Dermatology, Terahertz imaging, Adaptive imaging, THz modulation, Compressed sensing, Scar healing.
doi: 10.11906/TST.001-011.2019.03.01
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TST, Vol. 12, No. 1, PP. 12-25
(Invited paper) Dual THz comb spectroscopy
Takeshi Yasui *
Tokushima University, Graduate School of Technology, Industrial and Social Sciences,
2-1 Minami-Josanjima, Tokushima, Tokushima 770-8506, Japan
* Email: yasui.takeshi@tokushima-u.ac.jp
(Received April 24 2018)
Abstract: Terahertz (THz) frequency combs are innovative tools for broadband THz spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a frequency standard. However, usual THz spectrometer cannot resolve each mode of THz comb due to insufficient spectral resolution. Recently, dual THz comb spectroscopy appears as a new spectroscopic tool to acquire the mode-resolved THz comb spectrum with high resolution, high accuracy, broad spectral range, and moderate data acquisition time. In this paper, we have reviewed the recent progress of dual THz comb spectroscopy in our group.
Keywords: Terahertz spectroscopy, Frequency comb, Dual-comb spectroscopy, Gas spectroscopy
doi: 10.11906/TST.012-025.2019.03.02
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TST, Vol. 12, No. 1, PP. 26-32
Coherent terahertz radiation from Fabry–Pérot resonances via a special Smith-Purcell effect
Tao Zhao *, Min Hu, Renbin Zhong, Sen Gong and Shenggang Liu
Terahertz Research Center, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
* Email: forzhaotao@uestc.edu.cn
(Received 20 September 2018)
Abstract: A physical mechanism of multicolor coherent terahertz radiation is presented. We have found that, in a transmission metallic grating with deep enough slits, the multi-modes Fabry–Pérot resonances in the slit cavity can be efficiently excited by an electron beam moving atop the grating, and then transformed into radiation via a special Smith-Purcell effect. The radiation is coherent and highly directional, which is essentially different from the ordinary Smith-Purcell radiation. The radiation power density is an order of magnitude higher. The radiation frequency can be tuned by adjusting the grating parameters and beam energy. Based on this mechanism, the coherent, tunable, intense, and miniature terahertz radiation sources can be developed.
Keywords: Terahertz radiation, Fabry–Pérot resonances, Smith-Purcell effect
doi: 10.11906/TST.026-032.2019.03.03
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