Theoretical model : Transient temperature distribution in transmissive optical components for high power laser beam trains

In this paper, we will discuss the theoretical model that provides for the transient temperature distribution in all three orthogonal axis of a transmissive optic in a high power laser beam train. The mathematical transforms are set out for one, two and three dimensions for a time temperature history and the resulting optical deformation and subsequent loss of beam quality. The transforms will also provide maximum temperature rise, i.e., temperature differential, as a function of the laser power to allow for the transient thermal shock. Different optical materials are evaluated for providing trade-off of laser flux density, optical distortion and thermal shock. A great deal of pace is devoted to determining the temperature transient in an optic wherein the laser beam does not fill the whole aperture and the distortion arising from the different techniques of mounting.