Laser Polishing of Silica Rods

Lasers have been widely used in surface modification. In this research a CO2 continuous wave laser has been used to polish the slot surface of the silica rods. The strong absorption of the lO.6 um C02 radiation by the silica surface promotes the softening of a very thin layer of material that flows under the action of surface tension. As a result, a mirror smooth glassy surface has been formed which decreases the surface roughness without any substantial change in the surface geometries. The effect of laser to surface inclination angle on the requisite power requirement was assessed experimentally and theoretically. With laser beam scanning controlled by a computer aided design (CAD) database without specific tooling or human intervention, reliability and reproducibility of this process have been greatly improved compared to conventional fire polishing. The potential use of laser polishing as a post-processing step for freeform-fabricated parts is very promising.