PT Journal AU Walther, C Scalari, G Faist, J Beere, H Ritchie, D TI Low frequency terahertz quantum cascade laser operating from 1.6 to 1.8 THz SO Applied Physics Letters JI Appl. Phys. Lett. PY 2006 BP 231121(1 EP 3) VL 89 DE QCL; 360 uW at 1.6 THz AB The authors report a GaAs/Al0.1Ga0.9As quantum cascade laser based on a bound-to-continuum transition optimized for low frequency operation. High tunability of the gain curve is achieved by the Stark effect and laser emission is measured between 1.6 and 1.8 THz. Pulsed mode operation up to 95 K and continuous wave operation up to 80 K are reported. The dynamical range in current is as high as 43%. ER