title: Electrically switching transverse modes in high power THz quantum cascade lasers.
abstract: The design and fabrication of a high power THz quantum cascade laser (QCL), with electrically controllable transverse mode is presented. The switching of the beam pattern results in dynamic beam switching using a symmetric side current injection scheme. The angular-resolved L-I curves measurements, near-field and far-field patterns and angular-resolved lasing spectra are presented. The measurement results confirm that the quasi-TM(01) transverse mode lases first and dominates the lasing operation at lower current injection, while the quasi-TM(00) mode lases at a higher threshold current density and becomes dominant at high current injection. The near-field and far-field measurements confirm that the lasing THz beam is maneuvered by 25 degrees in emission angle, when the current density changes from 1.9 kA/cm(2) to 2.3 kA/cm(2). A two-dimension (2D) current and mode calculation provides a simple model to explain the behavior of each mode under different bias conditions.
authors.affiliation: Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, ON, Canada. sfatholo@ece.uwaterloo.ca
authors.forename: S
authors.initials: S
authors.lastname: Fathololoumi
authors.forename: E
authors.initials: E
authors.lastname: Dupont
authors.forename: S G
authors.initials: SG
authors.lastname: Razavipour
authors.forename: S R
authors.initials: SR
authors.lastname: Laframboise
authors.forename: A
authors.initials: A
authors.lastname: Delage
authors.forename: Z R
authors.initials: ZR
authors.lastname: Wasilewski
authors.forename: A
authors.initials: A
authors.lastname: Bezinger
authors.forename: G Z
authors.initials: GZ
authors.lastname: Rafi
authors.forename: S
authors.initials: S
authors.lastname: Safavi-Naeini
authors.forename: D
authors.initials: D
authors.lastname: Ban
authors.forename: H C
authors.initials: HC
authors.lastname: Liu
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D055053:Terahertz Radiation