Tunable sources and quantum cascade lasers in the mid-IR

The high power, room temperature operation of quantum cascade (QC) laser is based on a vertical transition and is optimized for high temperature operation by a design that reduces backfilling and enhances injection efficiency. A molecular beam epitaxy grown InP top cladding is incorporated, exhibiting a much lower thermal resistance and significantly improves the high temperature performance of the laser devices. Room temperature operation of QC laser has also been obtained in devices operating in second atmospheric window. The design is based on a `two well' vertical active region with emphasis on optimized resonant tunneling injection. QC lasers with long emission wavelengths have been designed and tested and deducted to be a powerful light source.