Terahertz quantum cascade lasers based on type II InGaAs/GaAsSb/InP

We report the demonstration of a terahertz quantum cascade laser based on the In(0.53)Ga(0.47)As/GaAs(0.51)Sb(0.49) type II material system. The combination of low effective electron masses and a moderate conduction band offset makes this material system highly suitable for such devices. The active region is a three-well phonon depopulation design and laser ridges have been processed in a double-metal waveguide configuration. The devices exhibit a threshold current density of 2 kA/cm(2), provide peak optical powers of 1.8 mW, and operate up to 102 K. Emission frequencies are in the range between 3.6 and 4.2 THz. (C) 2010 American Institute of Physics. [doi:10.1063/1.3532106]