High-power λ∼9.5μm quantum-cascade lasers operating above room temperature in continuous-wave mode

We report high-power continuous-wave (cw) operation of λ∼9.5μm quantum-cascade lasers to a temperature of 318K. A high-reflectivity-coated 19-μm-wide and 3-mm-long device exhibits cw output powers as high as 150mW at 288K and still 22mW at 318K. In cw operation at 298K, a threshold current density of 1.57kA∕cm2, a slope efficiency of 391mW∕A, and a maximum wall-plug efficiency of 0.71% are obtained. In pulsed operation, a maximum average power of 317mW is achieved at 49% duty cycle. The emission wavelength in cw mode is shifted from 9.524μm at 288K to 9.547μm at 313K near 1.05A drive current with a temperature tuning coefficient of 0.92nm∕K.