Room-temperature emission of GaAs/AlGaAs superlattice quantum-cascade lasers at 12.6 μm

We report on the lasing properties of quantum-cascade lasers that combine the advantage of strong electron confinement with the superior performance of superlattice structures. To achieve an optimum band offset between wells and barriers, we chose an Al content of the AlGaAs barriers of 45%. We fabricated both conventional Fabry–Pérot lasers, as well as single-mode-emitting distributed-feedback lasers. In pulsed mode, the lasers work well up to temperatures as high as 40 °C. The emission wavelength at this temperature is 12.6 μm. At 78 K, some lasers show a low threshold current density of 1.6 kA/cm2, while others show a high optical peak power of 240 mW.