title: Quantum cascade laser gain enhancement by front facet illumination.
abstract: Optical gain enhancement is demonstrated in a standard mid-infrared quantum cascade laser in pulse operation, using a near infrared illumination on the laser facet. An increase in the laser emission is observed, as well as greater dynamic range, threshold reduction, and a blue shift in the laser cavity modes. The optically induced gain increase allows for optical switching of the laser. All the changes have a nonlinear dependency on the illumination optical power and are attributed to the free carrier concentration increase and the electron transport change in the active region due to the near infrared illumination.
authors.affiliation: Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ 07030, USA. gchen1@stevens.edu
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Clyde G
authors.initials: CG
authors.lastname: Bethea
authors.forename: Rainer
authors.initials: R
authors.lastname: Martini
mesh_terms: D000669:Amplifiers, Electronic; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D054023:Lasers, Semiconductor; D008029:Lighting / Q000295:instrumentation*