title: Spectral behavior of a terahertz quantum-cascade laser.
abstract: In this paper, the spectral behavior of two terahertz (THz) quantum cascade lasers (QCLs) operating both pulsed and cw is characterized using a heterodyne technique. Both lasers emitting around 2.5 THz are combined onto a whisker contact Schottky diode mixer mounted in a corner cube reflector. The resulting difference frequency beatnote is recorded in both the time and frequency domain. From the frequency domain data, we measure the effective laser linewidth and the tuning rates as a function of both temperature and injection current and show that the current tuning behavior cannot be explained by temperature tuning mechanisms alone. From the time domain data, we characterize the intrapulse frequency tuning behavior, which limits the effective linewidth to approximately 5 MHz.
authors.affiliation: Physical Sciences Inc, 20 New England Business Center, Andover, Massachusetts 01810-1077, USA. Hensley@psicorp.com
authors.forename: J M
authors.initials: JM
authors.lastname: Hensley
authors.forename: Juan
authors.initials: J
authors.lastname: Montoya
authors.forename: M G
authors.initials: MG
authors.lastname: Allen
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.forename: L
authors.initials: L
authors.lastname: Mahler
authors.forename: A
authors.initials: A
authors.lastname: Tredicucci
authors.forename: H E
authors.initials: HE
authors.lastname: Beere
authors.forename: D A
authors.initials: DA
authors.lastname: Ritchie
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055053:Terahertz Radiation