title: Coupled cavity terahertz quantum cascade lasers with integrated emission monitoring.
abstract: We demonstrate the on-chip generation and detection of terahertz radiation in coupled cavity systems using a single semiconductor heterostructure. Multiple sections of a terahertz quantum cascade laser structure in a double-metal waveguide are optically coupled and operate either as a laser or an integrated emission monitor. A detailed analysis of the photon-assisted carrier transport in the active region below threshold reveals the detection mechanism for photons emitted by the very same structure above threshold. Configurations with a single laser cavity and two coupled laser cavities are studied. It is shown that the integrated detector can be used for spatial sensing of the light intensity within a coupled cavity.
authors.forename: Michael
authors.initials: M
authors.lastname: Krall
authors.forename: Michael
authors.initials: M
authors.lastname: Martl
authors.forename: Dominic
authors.initials: D
authors.lastname: Bachmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Deutsch
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Andrews
authors.forename: Werner
authors.initials: W
authors.lastname: Schrenk
authors.forename: Gottfried
authors.initials: G
authors.lastname: Strasser
authors.forename: Karl
authors.initials: K
authors.lastname: Unterrainer