It is the intent for the purpose of this paper to continue with the application of the Reverse Thermal Wave Model to problems associated with the damage thresholds and temperature gradients for optical components which are provided with optical thin films. This problem is particularly acute for those optical components which are part of a high power Continuous Wave laser system.
In this paper are descriptions of how the approximations provide techniques for evaluating the maximum threshold for optical thin films deposited on components with very thick and very thin optical faceplates. The Reverse Thermal Wave Model provides some rather dramatic results for those optical systems that are used for imaging in the infrared portion of the spectrum, in as much as these optical elements are generally very thin faceplates and may be subject to damage from very high power lasers.
Both mathematical descriptions and figures are provided to show the damage thresholds predicted by the model and correlated to one dimensional semi-infinite plate experimental data For the most part, authors have treated with infinite and semi-infinite walls. The attention for this article is to treat with those conditions that do not meet the boundary requirements for the semi-infinite plate. Given this boundary, the use of what we describe as the Reverse Thermal Wave Approximations will be implemented to allow the calculation of the transient temperature rise in thin optical faceplates. Equations are described and the regimes of their application are outlined Additionally, curves are generated to provide the reader examples of how to implement the equations.