title: Predictable surface emission patterns in terahertz photonic-crystal quantum cascade lasers.
abstract: We demonstrate a framework to understand and predict the far-field emission in terahertz frequency photonic-crystal quantum cascade lasers. The devices, which employ a high-performance three-well active region, are lithographically tunable and emit in the 104-120 microm wavelength range. A peak output power of 7 mW in pulsed mode is obtained at 10 K, and the typical device maximum operating temperature is 136 K. We identify the photonic-crystal band-edge states involved in the lasing process as originating from the hexapole and monopole modes at the G point of the photonic band structure, as designed. The theoretical far-field patterns, obtained via finite-difference time-domain simulations, are in excellent agreement with experiment. Polarization measurements further support the theory, and the role of the bonding wires in the emission process is elucidated.
authors.affiliation: Institut d'Electronique Fondamentale, Université Paris-Sud and CNRS, UMR8622, Orsay, France. yannick.chassagneux@u-psud.fr
authors.forename: Y
authors.initials: Y
authors.lastname: Chassagneux
authors.forename: R
authors.initials: R
authors.lastname: Colombelli
authors.forename: W
authors.initials: W
authors.lastname: Maineults
authors.forename: S
authors.initials: S
authors.lastname: Barbieri
authors.forename: S P
authors.initials: SP
authors.lastname: Khanna
authors.forename: E H
authors.initials: EH
authors.lastname: Linfield
authors.forename: A G
authors.initials: AG
authors.lastname: Davies
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D054023:Lasers, Semiconductor; D008962:Models, Theoretical; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D055053:Terahertz Radiation