title: Laser emission from a solar-pumped fiber.
abstract: We report the realization of a solar-pumped fiber laser (SPFL) using a double-clad (a center core/ an inner clad working also as optical waveguide/ an outer clad) Nd-doped fluoride optical fiber as a laser medium. With a compact off-axis parabolic mirror of 5 cm in aperture diameter, the natural sunlight is concentrated by a factor 10⁴, and introduced partly into the core of the fiber and partly into the inner clad in which the light is guided in some distance and transferred to the core after all. We have obtained clear laser spectrum characteristics with approximately 0.01 nm full-width-half-maximum of the laser line at the peak wavelength of 1053.7 nm, a low-lasing threshold of 49.1 mW, a slope efficiency of 6.6%, and a total efficiency of 1.76%. Further optimization of the medium properties, optical cavity, and concentration technique will yield higher efficiency and lower threshold.
authors.affiliation: Frontier Research Center, Toyota Central Research and Development Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan. mizunos@optics.tytlabs.co.jp
authors.forename: Shintaro
authors.initials: S
authors.lastname: Mizuno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hasegawa
authors.forename: Takenobu
authors.initials: T
authors.lastname: Suzuki
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Ohishi
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D053844:Lasers, Solid-State; D007909:Lenses