Miniaturized Terahertz Spectrometer

We propose to design and build a miniaturized pulsed terahertz (THz) spectrometer weighing less than 3.5 lbs, capable of real-time stand-off detection and identification of explosives and related compounds. The bandwidth of the THz system spans from 0.1 THz to 4 THz, and full waveform acquisition speeds up to 100 Hz. The room-temperature balanced detection system is one of the most sensitive THz wave receivers with a noise equivalent power less than 10-16 W/Hz^1/2. This system provides a dynamic range larger than 10,000, and real time spectral measurement. The miniaturized THz system consists of an ultra-compact THz source, a balanced photonic detector, and a novel time delay stage. They are integrated with a specially designed optical and THz optical system. Benefiting from the compact, lightweight and highly efficient fiber laser, the size of the THz source in the THz system will be less than 90 cubic inches, and the weight including power supply will be less than 3.5 pounds. The pulsed THz wave emitter will be an optimized photoconductive antenna. Its high energy conversion efficiency promises a peak THz power over 1 Watt even with a low-power fiber laser as the excitation source.