Watt-Level Room Temperature Continuous-Wave Operation of Quantum Cascade Lasers With λ >10 μm

In this paper, watt-level continuous-wave (CW) output powers at wavelengths longer than 10 μm are demonstrated at room temperature with quantum cascade lasers (QCLs). CW output power of 1.15 W is demonstrated at λ ~ 10.3 μm for a QCL which has a 6-mm-long cavity and a 14-μm-wide stripe. CW output power of 1.3 W is demonstrated at λ ~ 10.7 μm for a QCL which has 6-mm-long cavity and 11.5-μm width, with a CW threshold current of 1.96 kA/cm2. Moreover, 1-W kink-free CW output power is demonstrated with a laser with a 9.5-μm-wide stripe. The maximum pulsed and CW wall plug efficiencies reached 10.4% and 4.8%, respectively, for the QCLs with λ ~ 10.7 μm.