title: Alignment-stabilized interference filter-tuned external-cavity quantum cascade laser.
abstract: A passively alignment-stabilized external cavity quantum cascade laser (EC-QCL) employing a "cat's eye"-type retroreflector and an ultra-narrowband transmissive interference filter for wavelength selection is demonstrated and experimentally investigated. Compared with conventional grating-tuned ECQCLs, the setup is nearly two orders of magnitude more stable against misalignment of the components, and spectral fluctuation is reduced by one order of magnitude, allowing for a simultaneously lightweight and fail-safe construction, suitable for applications outdoors and in space. It also allows for a substantially greater level of miniaturization and cost reduction. These advantages fit in well with the general properties of modern QCLs in the promise to deliver useful and affordable mid-infrared-light sources for a variety of spectroscopic and imaging applications.
authors.forename: Jan
authors.initials: J
authors.lastname: Kischkat
authors.forename: Mykhaylo P
authors.initials: MP
authors.lastname: Semtsiv
authors.forename: Mikaela
authors.initials: M
authors.lastname: Elagin
authors.forename: Grygorii
authors.initials: G
authors.lastname: Monastyrskyi
authors.forename: Yuri
authors.initials: Y
authors.lastname: Flores
authors.forename: Sergii
authors.initials: S
authors.lastname: Kurlov
authors.forename: Sven
authors.initials: S
authors.lastname: Peters
authors.forename: W Ted
authors.initials: WT
authors.lastname: Masselink