Epi-Side-Down-Mounted Interband Cascade Laser with Improved Top Cladding Layer

In this Phase I program, we will assess semiconductor diode laser technology to determine which semiconductor lasers are the best candidates for meeting infrared countermeasure (IRCM) requirements in each of the three IRCM wavelength bands. A central focusof the effort will be to test the feasibility and merits of a new design for type-II interband cascade (IC) lasers and a new method for their fabrication. These mid-IR IC lasers, based on cascaded type-II InAs/GaInSb/AlSb quantum wells, have recentlydemonstrated pulsed operation at 300K in an epi-side-up geometry, but cw operation has been severely limited by heat accumulation in the device active regions. The new IC laser design also has a top cladding layer composed of AlAsSb, replacing theInAs/AlSb strained layer superlattice cladding layer used in earlier designs. This new cladding material combined with the novel epi-side-down fabrication method is intended to conduct heat more efficiently from the active region to the heat sink enablingcw operation at high temperatures. The success of this project would have a far-reaching impact. First, the successful development of adequate sources for all IRCM bands would enable all-semiconductor-laser-based IRCM source modules. These could then leadto a significant improvement of IRCM systems. IR guided missiles are credited with up to 80% of total air losses throughout the 1970's and 80's. Seven of 16 allied losses during the Gulf War were directly attributed to this threat. It presently representsa tremendous threat to large transport aircraft, which must rely on effective IRCM. The potential to enhance military survivability is quite an adequate dividend in itself. Nevertheless, other application areas would also be positively impacted. Theseinclude sources for free-space communications (for both civilian and military applications) and sources for local and remote chemical sensing systems serving the needs of several industries (e.g., industrial process controls, pollution monitoring, medicaldiagnostics, explosives detection, etc.).