All-Optical Terahertz Spectrophotometer for Biological Detection

In today's environment environment of the the global war on terrorism, there is a pressing need to strengthen on-base and aviation securdevelopity by developing next-generationnovel inspection sensing technology capable of enhanced for the detection and identification of chemical and biological concealed threatsweapons (CBW) and explosives in both battlefield situations as well as civilian settingspackages and on personnel. Although optoelectronic sensing in the terahertz (THz) frequency region is being investigated intensely for this application, serious technical challenges in terms of source output power, detector sensitivity, and component integration prevent the realization of a compact, robust and reliable THz sensor that can be used to detect and identify threat agents effectively in the field. Laser-based generation of coherent tunable Since tAs the U.S. Air Force utilizes the commercial shipping infrastructure for its worldwide shipping needs, such enhanced inspection technology is vital to the base security of its bases. Contemporary portal security systems based on X-ray and magnetic screening are seriously limited in their capabilities for detecting a wide variety of potentially dangerous materials - weapons made out of ceramics, plastics, or composites; explosives; and substances associated with chemical, biological and nuclear weapons. Coherent THz radiation coupled with phase coherent electro-optic detection imaging (CTI) presents significant potential as an advanced safe, non-ionizingnvasive sensing technology probe for both personnel and packages with no health risks, sub-millimeter spatial resolution and with enhanced capabilities for compositional analysis and automated recognition of CBW threats. Foster-Miller proposes to design and develop an "All-Optical" laser-based CTI Coherent THz Spectrometer (OCTS) based on highly efficient nonlinear optical THz generation and detectionsystem that incorporates the optoelectronic generation of spectrally agile continuous wave (CW) THz radiation coupled with phase-coherent detection using non-resonant electro-optic (EO) sampling. In combination with efficient software algorithms that perform image deconvolution and target recognition, such a system willto permit the real time interrogation of packages and personnel in complementary transmissive and reflective modes. The proposed Phase I will effort will demonstrate the efficacy of the OCTSI to the problem at hand by building integrating component technologies into a compact table-top system to that can conductperform rapid and accurate detailed spectroscopic studies measurements of various harmful substances and develop appropriate signal processing software and hardware for the detection and identification of concealed on biological materials over the widest possible THz frequency range. (P-040251)