title: Terahertz ambipolar dual-wavelength quantum cascade laser.
abstract: Terahertz frequency quantum cascade lasers (THz QCLs) are compact solid-state sources of terahertz radiation that were first demonstrated in 2002. They have a broad range of potential applications ranging from gas sensing and non-destructive testing, through to security and medical imaging, with many polycrystalline compounds having distinct fingerprint spectra in the terahertz frequency range. In this article, we demonstrate an electrically-switchable dual-wavelength THz QCL which will enable spectroscopic information to be obtained within a THz QCL-based imaging system. The device uses the same active region for both emission wavelengths: in forward bias, the laser emits at 2.3 THz; in reverse bias, it emits at 4 THz. The corresponding threshold current densities are 490 A/cm(2) and 330 A/cm(2), respectively, with maximum operating temperatures of 98K and 120 K.
authors.affiliation: Institute of Microwaves and Photonics, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom. l.j.m.lever@leeds.ac.uk
authors.forename: L
authors.initials: L
authors.lastname: Lever
authors.forename: N M
authors.initials: NM
authors.lastname: Hinchcliffe
authors.forename: S P
authors.initials: SP
authors.lastname: Khanna
authors.forename: P
authors.initials: P
authors.lastname: Dean
authors.forename: Z
authors.initials: Z
authors.lastname: Ikonic
authors.forename: C A
authors.initials: CA
authors.lastname: Evans
authors.forename: A G
authors.initials: AG
authors.lastname: Davies
authors.forename: P
authors.initials: P
authors.lastname: Harrison
authors.forename: E H
authors.initials: EH
authors.lastname: Linfield
authors.forename: R W
authors.initials: RW
authors.lastname: Kelsall
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D011789:Quantum Theory; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055053:Terahertz Radiation