High-temperature mid-IR type-II quantum well lasers

A series of optically-pumped type-II quantum well lasers with emission wavelengths between 3.2 mu m and 4.5 mu m have displayed stimulated emission up to ambient operating temperatures. The 4-constituent design combines the advantages of excellent carrier confinement, potential for significant Auger suppression, and a 2D density-of-states for both electrons and holes. For a device emitting at 4.5 mu m, the characteristic temperature was 41 K and a peak output power exceeding 2 W/facet was observed at 200 K. Auger coefficients extracted from the threshold pump intensity confirm that Auger losses at 300 K were suppressed by at least a factor of two. We also discuss modeling results for a type-II interband cascade laser structure which is predicted to yield much higher output powers and operating temperatures than conventional bipolar diode lasers, as well as lower threshold currents than the intersubband quantum cascade laser.