Influence of the beveling of a ruby crystal on the damage in its interior

It was found that a beveled edge of the flat end of a cylindrical ruby rod, given a surface finish of grade 10–12, acted as a focusing surface. The edge concentrated laser radiation present in the resonator inside the ruby rod and this caused local damage. The experimental results were in good agreement with theoretical calculations. It was found that when the angle of inclination of the bevel with respect to the rod axis was increased, the location of the damage region moved away from the flat end.