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Proceedings Paper

Biological and chemical sensing with electronic THz techniques
Author(s): Min Ki Choi; Alan D. Bettermann; Daniel W. van der Weide
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Paper 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.

Paper Details

Date Published: 27 February 2004
PDF: 9 pages
Proc. SPIE 5268, Chemical and Biological Standoff Detection, (27 February 2004); doi: 10.1117/12.518462
Show Author Affiliations
Min Ki Choi, Univ. of Wisconsin/Madison (United States)
Alan D. Bettermann, Univ. of Wisconsin/Madison (United States)
Daniel W. van der Weide, Univ. of Wisconsin/Madison (United States)

Published in SPIE Proceedings Vol. 5268:
Chemical and Biological Standoff Detection
James O. Jensen; Jean-Marc Theriault, Editor(s)

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