Laser polishing of silica slotted rods

Abstract

Lasers have been widely used in surface modification. In the present research, a CO₂ continuous wave laser has been used to polish slot surfaces of silica rods. Strong absorption of 10.6 μm CO₂ radiation by the silica surface promotes softening of a very thin layer of material that flows under the action of surface tension forces. A smooth surface forms, which decreases the surface roughness without substantial change in surface geometry. The effect of laser-surface inclination angle on the requisite power requirement has been assessed experimentally and theoretically. Using a computer controlled laser beam scanning system, reliability and reproducibility have been greatly improved compared with an alternative surface finishing method, manual fire polishing.