Terahertz quantum cascade lasers and real-time 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 similar to 170 K, the highest CW operating temperature of 117 K, the longest wavelength of similar to 190 mu m, and the highest output power levels of similar to 250 mW. Using these lasers and a 320x240 pixel focal-plane array camera, real-time THz imaging is performed at a rate of 20 frames/second.