High-Brightness from an Unstable Resonator Mid-IR Semiconductor Laser

We describe high-brightness, broad-area mid-IR semiconductor lasers. These devices were fabricated in our laboratory using a commercial solid-source MBE system, configured specifically for antimonide alloy deposition. The laser structures incorporated fourteen type-II quantum wells embedded in thick waveguide/absorber regions composed of In
_0.2
Ga
_0.8
As
_y
Sb
_1-y
. Each type-II well is comprised of a ~24 Aring thick In
_0.4
Ga
_0.6
Sb hole bearing layer, which is sandwiched in between two coupled InAs electron wells; as we vary the InAs thickness from 3 to 30 Aring we tune the laser from 2.5 μm to 9.5 μm