Time-domain terahertz spectroscopy and applications on drugs and explosives

W. H. Fan, W. Zhao, G. H. Cheng, A. D. Burnett, P. C. Upadhya, J. E. Cunningham, E. H. Linfield, A. G. Davies

科研成果: 书/报告/会议事项章节会议稿件同行评审

2 引用 (Scopus)

摘要

Many materials of interest to the forensic and security services, such as explosives, drugs and biological agents, exhibit characteristic spectral features in the terahertz (THz) frequency range. These spectral features originate from inter-molecular interactions, involving collective motions of molecules. Broadband THz time-domain spectroscopy (THz-TDS) system have been used to analyze a number of drugs-of-abuse and explosives that are of interest to the forensic and security services. These samples ranged from crystalline powders, pressed into pellets, to thin sheets of plastic explosives, and all being measured in transmission geometry in the frequency range 0.1-8 THz. To well understand the nature of the observed spectral features and the effects of thermal broadening on these far-infrared signatures, temperature-dependent THz-TDS measurements have also been performed at temperatures as low as 4 K, especially for two types of cocaine. Well-resolved low-frequency absorption peaks were observed in the frequency range 0.1-3 THz with high resolution. Some of absorption peaks were found clearly to become more intense and shift to higher frequencies as the temperature was reduced. The results confirm that the low-frequency collective modes are highly sensitive to the structural and spatial arrangement of molecules. Furthermore, a number of common postal packaging materials made from paper, cardboard, even several types of plastic, have been tested with drug sample to assess the ability of THz-TDS in a hostile detection environment.

源语言英语
主期刊名Terahertz Photonics
DOI
出版状态已出版 - 2008
已对外发布
活动Terahertz Photonics - Beijing, 中国
期限: 12 11月 200714 11月 2007

出版系列

姓名Proceedings of SPIE - The International Society for Optical Engineering
6840
ISSN(印刷版)0277-786X

会议

会议Terahertz Photonics
国家/地区中国
Beijing
时期12/11/0714/11/07

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