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

We report high-power continuous-wave (cw) operation of lambda similar to 9.5 mu m quantum-cascade lasers to a temperature of 318 K. A high-reflectivity-coated 19-mu m-wide and 3-mm-long device exhibits cw output powers as high as 150 mW at 288 K and still 22 mW at 318 K. In cw operation at 298 K, a threshold current density of 1.57 kA/cm(2), a slope efficiency of 391 mW/A, and a maximum wall-plug efficiency of 0.71% are obtained. In pulsed operation, a maximum average power of 317 mW is achieved at 49% duty cycle. The emission wavelength in cw mode is shifted from 9.524 mu m at 288 K to 9.547 mu m at 313 K near 1.05 A drive current with a temperature tuning coefficient of 0.92 nm/K. (c) 2006 American Institute of Physics.