title: Broadband tuning of continuous wave quantum cascade lasers in long wavelength (> 10 μm) range.
abstract: Broadband spectral tuning in the long wavelength range (greater than 10 μm) was demonstrated with an external-cavity quantum cascade laser. The tunable wavelength of the laser ranged from 9.5 to 11.4 μm (176 cm(-1); corresponding to 18% of the center wavelength) in continuous wave (cw) operation at room temperature, without any anti-reflection coating. The gain chip based on the anti-crossed dual-upper-state (DAU) design provided a cw lasing up to 300 K, with a low threshold current density of 2.1 kA/cm2. The highly stable broadband spectral tuning and high laser performance were enabled by the spectrally homogeneous gain profile of the anti-crossed DAU active region.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Dougakiuchi
authors.forename: Kazuue
authors.initials: K
authors.lastname: Fujita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sugiyama
authors.forename: Akio
authors.initials: A
authors.lastname: Ito
authors.forename: Naota
authors.initials: N
authors.lastname: Akikusa
authors.forename: Tadataka
authors.initials: T
authors.lastname: Edamura