Determination of Pulsed CO2 Laser Damage Thresholds of Optical Surfaces

摘要

An experimental technique is described for determining the damage thresholds of glass and plastic optical material surfaces, opaque to laser radiations, when irradiated with a pulsed TEA-CO2 laser. Use of a probit analysis to estimate the irradiance required for a 50% probability of damage gives threshold levels of 4.0 J/(sq cm) for fused silica, 2.1 J/(sq cm) for soda-lime glass, 2.3 J/(sq cm) for polycarbonate, 2.3 J/(sq cm) for acrylic and 1.7 J/(sq cm) for polystyrene plastics. The significance of the statistical distributions observed in attributing various mechanisms to the damage is discussed. Finally, some improvements are suggested to make the measurements more accurate. (Author)