Semiconductor lasers for efficient and reliable CW operation in the mid- and far-infrared: Intersubband quantum-box lasers

Intersubband quantum-box (IQB) lasers, that is, devices consisting of 2D arrays of single-stage intersubband QB emitters, are proposed, as an alternative to 30-stage quantum-cascade (QC) devices, as sources for efficient room-temperature (RT) emission in the mid- and far-IR (3-5 and 8-12 μm) wavelength ranges. Preliminary results include: (1) the realization of the first mid-IR (λ = 4.7 μm) single-stage emitters operating at RT; (2) etch-and-regrowth at the nanoscale level by employing in situ gas etching and MOCVD regrowth; (3) the formation of 30 nm-diameter SiO2 posts on 80 nm centers, thus forming the mask for the fabrication of IQBs via in situ etch and regrowth. © World Scientific Publishing Company.