Ring-like damage morphologies produced by continuous-wave laser irradiation

The surface damage morphologies produced by continuous-wave laser irradiation of coated optics were measured and analyzed. A few laser damage morphologies were observed to be bull’s-eye patterns. It is noted that the bull’s-eye pattern has some similarities to Bessel distributions of the form found in solutions of basic heat transfer or surface acoustic wave problems, which may indicate a relationship. If these morphologies are truly thermal phenomenon, then the Bessel ring diameter would be a function of thermal diffusivity. This might indicate that the ring diameter could be used to assess the resistance of a film to laser damage.