Multi-color Quantum Cascade Mid-Infrared Sources at 2.5 to 5 ym

We propose to develop multi-color mid-infrared (IR) sources at 2.5 to 5 um based on InAs/InGaSb type-II quantum cascade (QC) structures. A compact mid-IR dual wavelength source could be extremely useful for the environmental gas and pollutant sensing, such as differential absorption lidar, where the light scattering has to be evaluated and compared at two different wavelengths. Recently, we have demonstrated room-temperature optically pumped lasers from 2.9 to 4.6 um based on InAs/InGaSb/AlSb type-II quantum wells. For 4.5-1lm devices, lasing was observed up to 310 K, and the peak output power per facet was more than 3 65 W at 160 K and about 360 mW at 280 K. For type-II QC lasers, lasing was observed up to 285 K at 3.5 pm, and a peak output power of 0.5 W/facet at 3.85 ,um was obtained with 1 ps current pulses at 80 K, with a differential quantum efficiency of 131%. The Phase I effort will be directed towards the demonstration of the CW operation of two-color light emitting diode at high temperature.