27 February 2004 Biological and chemical sensing with electronic THz techniques
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Proceedings Volume 5268, Chemical and Biological Standoff Detection; (2004) https://doi.org/10.1117/12.518462
Event: Optical Technologies for Industrial, Environmental, and Biological Sensing, 2003, Providence, RI, United States
Abstract
The terahertz regime (0.1 to 10 THz) is rich with emerging possibilities in sensing, imaging and communications, with unique applications to screening for weapons, explosives and biohazards, imaging of concealed objects, water content and skin. Here we present initial surveys to evaluate the possibility of sensing bacterial spores and chemical material using field-deployable electronic terahertz techniques that use short-pulse generation and coherent detection based on nonlinear transmission lines and diode sampling bridges. We also review the barriers and approaches to achieving greater sensing-at-a-distance (stand-off) capabilities for THz sensing systems. We have made several reflection measurements of metallic and non-metallic targets in our laboratory, and have observed high contrast relative to reflection from skin. In particular, we have taken small quantities of materials such as dimethyl methylphosphonate (DMMP) and several variants of Bacillus spores, and measured them in transmission and in reflection using a broadband pulsed electronic THz reflectometer. The pattern of reflection versus frequency gives rise to signatures that indicate specificity of the target. Although more work needs to be done to reduce the effects of standing waves through time gating or attenuators, the possibility of mapping out this contrast for imaging and detection is very attractive.
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Min Ki Choi, Min Ki Choi, Alan D. Bettermann, Alan D. Bettermann, Daniel W. van der Weide, Daniel W. van der Weide, } "Biological and chemical sensing with electronic THz techniques", Proc. SPIE 5268, Chemical and Biological Standoff Detection, (27 February 2004); doi: 10.1117/12.518462; https://doi.org/10.1117/12.518462
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