title: THz quantum cascade lasers with wafer bonded active regions.
abstract: We demonstrate terahertz quantum-cascade lasers with a 30 μm thick double-metal waveguide, which are fabricated by stacking two 15 μm thick active regions using a wafer bonding process. By increasing the active region thickness more optical power is generated inside the cavity, the waveguide losses are decreased and the far-field is improved due to a larger facet aperture. In this way the output power is increased by significantly more than a factor of 2 without reducing the maximum operating temperature and without increasing the threshold current.
authors.affiliation: Photonics Institute and Center for Micro- and Nanostructures, Vienna University of Technology, Gusshausstrasse 29, A-1040 Vienna, Austria. martin.brandstetter@tuwien.ac.at
authors.forename: M
authors.initials: M
authors.lastname: Brandstetter
authors.forename: C
authors.initials: C
authors.lastname: Deutsch
authors.forename: A
authors.initials: A
authors.lastname: Benz
authors.forename: G D
authors.initials: GD
authors.lastname: Cole
authors.forename: H
authors.initials: H
authors.lastname: Detz
authors.forename: A M
authors.initials: AM
authors.lastname: Andrews
authors.forename: W
authors.initials: W
authors.lastname: Schrenk
authors.forename: G
authors.initials: G
authors.lastname: Strasser
authors.forename: K
authors.initials: K
authors.lastname: Unterrainer
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D011789:Quantum Theory; D012031:Refractometry / Q000295:instrumentation*; D055053:Terahertz Radiation