title: Tunable high-power narrow-spectrum external-cavity diode laser at 675 nm as a pump source for UV generation.
abstract: High-power narrow-spectrum diode laser systems based on tapered gain media in an external cavity are demonstrated at 675 nm. Two 2 mm long amplifiers are used, one with a 500 μm long ridge-waveguide section (device A), the other with a 750 μm long ridge-waveguide section (device B). Laser system A based on device A is tunable from 663 to 684 nm with output power higher than 0.55 W in the tuning range; as high as 1.25 W output power is obtained at 675.34 nm. The emission spectral bandwidth is less than 0.05 nm throughout the tuning range, and the beam quality factor M(2) is 2.07 at an output power of 1.0 W. Laser system B based on device B is tunable from 666 to 685 nm. As high as 1.05 W output power is obtained around 675.67 nm. The emission spectral bandwidth is less than 0.07 nm throughout the tuning range, and the beam quality factor M(2) is 1.13 at an output power of 0.93 W. Laser system B is used as a pump source for the generation of 337.6 nm UV light by single-pass frequency doubling in a bismuth triborate (BIBO) crystal. An output power of 109 μW UV light, corresponding to a conversion efficiency of 0.026% W(-1), is attained.
authors.affiliation: DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Frederiksborgvej 399, P.O. Box 49, DK-4000 Roskilde, Denmark. mchi@fotonik.dtu.dk
authors.forename: Mingjun
authors.initials: M
authors.lastname: Chi
authors.forename: Ole Bjarlin
authors.initials: OB
authors.lastname: Jensen
authors.forename: Götz
authors.initials: G
authors.lastname: Erbert
authors.forename: Bernd
authors.initials: B
authors.lastname: Sumpf
authors.forename: Paul Michael
authors.initials: PM
authors.lastname: Petersen
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D001881:Borates / Q000737:chemistry*; D004867:Equipment Design; D054023:Lasers, Semiconductor; D055095:Optics and Photonics; D014466:Ultraviolet Rays
chemical_list: D001881:Borates; D001729:Bismuth