title: High-power room-temperature continuous-wave mid-infrared interband cascade lasers.
abstract: We demonstrate cw output powers >290 mW into a nearly diffraction-limited (M² ≈2.2) output beam from an interband cascade laser operating at λ = 3.6-3.7 μm at room temperature. The interband cascade laser was designed for nearly equal electron and hole populations in the active region with heavy electron-injector doping, and was processed into narrow ridges mounted epitaxial side down on a copper heat sink. A 15.7-μm-wide, 4-mm-long ridge with the back facet coated for high reflection (HR) and an anti-reflection-coated front facet produced 253 mW of cw output power at T = 25°C into a beam with M² ≈2.7. Furthermore, corrugating the sidewalls of the ridge leads to a 20% improvement in the brightness. A 15.7-μm-wide, 0.5-mm-long ridge with an HR-coated back facet and an uncoated front facet exhibited a maximum cw wall-plug efficiency of nearly 15% at room temperature.
authors.affiliation: Code 5613, Naval Research Laboratory, Washington, DC 20375, USA.
authors.forename: William W
authors.initials: WW
authors.lastname: Bewley
authors.forename: Chadwick L
authors.initials: CL
authors.lastname: Canedy
authors.forename: Chul Soo
authors.initials: CS
authors.lastname: Kim
authors.forename: Mijin
authors.initials: M
authors.lastname: Kim
authors.forename: Charles D
authors.initials: CD
authors.lastname: Merritt
authors.forename: Joshua
authors.initials: J
authors.lastname: Abell
authors.forename: Igor
authors.initials: I
authors.lastname: Vurgaftman
authors.forename: Jerry R
authors.initials: JR
authors.lastname: Meyer