ABSTRACT
THz quantum cascade lasers based on a novel buried cavity geometry are demonstrated by combining surface plasmon waveguides with proton implantation. Double metal devices are realized with emission at 2.8 THz, displaying ultra-low threshold currents of 19 mA (127A/cm2) at 4K in both pulsed and continuous wave operation. Owing to the semiconductor material on both sides of the active region and to the narrow width of the top metal strip, the thermal properties of these devices are greatly improved. A decrease of the thermal resistance by over a factor of two compared to standard ridge double-metal lasers of similar size has been measured.
