Two-Layer Film Damage Threshold

Interest in numerical analysis of laser optical systems, such as gold mirrors, has a long hystory [1]. In this paper authors analyse the response of gold-cromium film on subpicosecond laser action of low intensity using a two-temperature model (TTM). The damage threshold of gold can be increased by using a substrate material (second layer) with high electron-lattice coupling factor. This results in intensive heat sink from the gold layer. For fixed entire thickness of the double-layer film, there is an optimal proportion of top and bottom layers for which the damage threshold is highest possible.

[1] T. Q. Qiu and C. L. Tien. Femtosecond laser heating of multi-layer metals—I. Analysis // Int. J. of Heat and Mass Trans. 1994, Vol.37, No.17, pp.2789-2797.