Dual-Wavelength Quantum Cascade Laser with Two Optical Transitions in Each Active Region

Abstract

We report on a novel quantum cascade laser design that utilizes wide active region quantum wells to create a lasing transition between the second- and first-excited states of the constituent wells. Electroluminescence and lasing spectra confirm the presence of the optical transition at the expected energy, but also show the conventional transition between energy levels resulting from excited and ground states of the original quantum wells. As a result, the laser produces simultaneous dual-wavelength emission at 8.2 µm and 9.3 µm.