Terahertz quantum cascade lasers and video-rate THz imaging

Based on a robust THz gain medium that rapidly depopulates the lower state using resonant LO-phonons and a novel metal-metal waveguide structure for mode confinement, we have developed THz quantum-cascade lasers with many performance records. These include but not limited to: the highest pulsed operating temperature of ~170 K, the highest CW operating temperature of 117 K, long wavelength of ~190 mum, and the highest output power levels of-250 mW. Using these lasers and a 320 times 240 pixel focal-plane array camera, real-time THz imaging is performed at a video rate of 20 frames/second.