High-power cw λ∼4 μm quantum-cascade lasers (QCLs) are demonstrated. The effect of different cavity length and laser die bonding is also investigated. For a high-reflectivity-coated 11-μm -wide and 4-mm -long epilayer-down bonded QCL, cw output powers as high as 1.6 W at 80 K and 160 mW at 298 K are obtained, and the cw operation is achieved up to 313 K with 12 mW. The laser exhibits a threshold current density of 1.96 kA cm2, a slope efficiency of 737 mWA, and a maximum wall-plug efficiency of 0.9% under cw mode at 298 K. In pulsed mode, a maximum average power of 552 mW at 298 K is achieved at 45% duty cycle and a characteristic temperature is 176 K from 80 to 393 K.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)