文档介绍：F2-Laser-Based Fabrication of Fabry-Perot Cavities in Fused Silica
and Sapphire Optical Fibres
V R Machavaram1, R A Badcock, G F Fernando*1
1Department of Metallurgy and Materials, University of Birmingham, England, UK.
ABSTRACT
The majority of the reported applications on 157 nm ablation of fused silica and sapphire were concerned with surface
micromachining, where the depth of ablation ranges from few hundreds of nanometres to several micrometres. The
control of surface morphology and wall-angle of the microstructures was found to be difficult with increasing ablation
depth. In this paper, the performance of a Kohler-based illumination in conjunction with a low-numerical aperture
imaging system for micromachining cavities through the diameter of standard silica optical fibres and sapphire fibres is
presented. Roughness of wall surface and tapering of cavities at different energy densities have been investigated. Near-
parallel walled cavities micromachined in silica fibres produced Fabry-Perot fringes as a result of interference of light
undergoing Fresnel reflections at the cavity walls. A technique to control the ablation depth of cavities in optical fibres
via in-situ monitoring of laser-induced fluorescence is developed.
Keywords: F2-laser,