Threshold conditions for the damage to single crystals of calcium chloride acted on by cw CO2 laser radiation

An experimental and theoretical investigation was made of the threshold conditions for the damage to single crystals of KCl caused by focused radiation from a 5-kW cw electron-beamcontrolled CO₂ laser. The aim was to establish design criteria for exit windows in industrial CO and CO₂ lasers having a high average output power. The damage was found to start on the front surface of a crystal due to the high intensity of shear stresses. A study was made of the influence of the nature of surface treatments of crystals on their optical strength.