Compact Intense THz Unit for Eye-safe Standoff Explosive Detection

We will develop a compact THz system with standoff spectroscopic detection capability, using an intense 1-μm Yb fiber laser with a tilted optical pulse wave-front to excite a nonlinear optical crystal (such as, LiNbO3) as the THz emitter, and a balanced electric-optic (EO) crystal incorporated with a quartz lens as the detector. The proposed unit will have THz average power greater than 1 mW and signal-to-noise ratio with real-time detection at 10 meters better than 1,000. Explosives and related compounds (ERCs) feature broad spectral signatures that are separable from narrow water absorption spectral lines using our proposed novel algorithm. Improvements in the emitter, detector and software will significantly improve the signal/noise ratio of the device by at least two orders with a bandwidth over 3.0 THz, and consequently, extend the standoff detection distance from ~10 m to over 30 m.