Thermal theory of convectively cooled mirrors, windows for CW and repetitively pulsed lasers

A time-dependent, two-dimensional theory is developed to calculate thermally induced deformation of optical components, such as mirrors and windows. The solids are modeled as thin plates of finite thickness. The theory includes surface heating on both surfaces and bulk heating because the laser beam is either reflected from or transmitted through the solids. Convective cooling on both surfaces is accounted for by use of the average heat transfer coefficients over the surfaces. The laser beam, which can be either CW or repetitively pulsed, is assumed to be axially symmetric. Results predicted for the CW case compare well with results from actual experiments.