Continuous-wave operation of λ∼4.8 μm quantum-cascade lasers at room temperature

Continuous-wave (cw) operation of quantum-cascade lasers emitting at lambdasimilar to4.8 mum is reported up to a temperature of 323 K. Accurate control of layer thickness and strain-balanced material composition is demonstrated using x-ray diffraction. cw output power is reported to be in excess of 370 mW per facet at 293 K, and 38 mW per facet at 323 K. Room-temperature average power measurements are demonstrated with over 600 mW per facet at 50% duty cycle with over 300 mW still observed at 100% (cw) duty cycle. (C) 2004 American Institute of Physics.