Heating process and damage threshold analysis of Au film coated on Cu substrate for femtosecond laser

The heating processes of a two-layer film assembly of Au padded with Cu irradiated by femtosecond laser pulse are studied using a two-temperature model. It is found that the chosen substantially influence the energy transport, and consequently the temperature variation, and thermal equilibrium time. At the same laser fluence, the different thickness of gold film leads to a change of gold surface temperature. By choosing the thickness of the gold layer in the two-layer film assemblies, the damage threshold of the gold film can be maximized. The results can be used to optimize the damage threshold of gold coating optical components.

► The two-layer film of Au padded with Cu can change energy transport processes.
► The different thickness of gold film leads to a change of surface temperature.
► By adjusting the thickness of gold coating layer, it can maximize damage threshold.
► The results can be used for increasing damage threshold of coating optical component.