The superior thermal and optical properties of transparent polycrystalline ceramics make them attractive alternatives to glass-based materials for laser gain media. Fibers have other advantages of compactness, vibration-resistance, and reduced cooling requirements. Recently it was found that surface roughness caused by grain boundary grooving dominated optical scattering even though there were other scattering sources in the fiber. Therefore, a lot of effort went to fabrication of fibers with smooth surfaces. A mechanical polishing method for polycrystalline YAG fibers was developed. The fiber surface roughness was reduced, while maintaining a circular cross-section. Surface-polished 1.5% Ho-doped polycrystalline YAG fiber, 62 mm long with 31 μm diameter, was fabricated, and lasing was demonstrated from this fiber. Effects of surface-polishing on the surface roughness and scattering coefficient are presented, and lasing characteristics are discussed.

Date Published: 1 May 2017
PDF: 7 pages
Proc. SPIE 10192, Laser Technology for Defense and Security XIII, 101920B (1 May 2017); doi: 10.1117/12.2262673

Published in SPIE Proceedings Vol. 10192:
Laser Technology for Defense and Security XIII
Mark Dubinskii; Stephen G. Post, Editor(s)