Electrically switching transverse modes in high power THz quantum cascade lasers.
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.
Fathololoumi
S
S
Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, ON, Canada. sfatholo@ece.uwaterloo.ca
Dupont
E
E
Razavipour
S G
SG
Laframboise
S R
SR
Delage
A
A
Wasilewski
Z R
ZR
Bezinger
A
A
Rafi
G Z
GZ
Safavi-Naeini
S
S
Ban
D
D
Liu
H C
HC
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