Heating by laser irradiation – first trials with simple construction materials

The project “Laser weapons and protection” within the research program “Air defense, unmanned air systems and lasers” aims to develop high-power lasers as countermeasures against incoming projectiles, drones and the like. This report discusses the heating of typical construction materials for the defense industry by laser radiation. The report also describes the laser damage laboratory at FFI and results from there. The measurements are compared to simulations based on the theory of heat conduction. This theoretical model is described in detail, including its numerical implementation. There is a strong correspondence between modeled and measured temperature increase for most of the materials examined if one disregards the measured values for reflectance at low power and room temperature. This parameter must be heavily adjusted to get a good match between theory and experiment at high power and during heating – probably because the coating on the materials burns up quickly and the reflectance thus changes considerably during the experiment. The knowledge from such experiments will be used further in work with laser weapons in several ways. On one hand, it is important to understand how possible military targets can be damaged by a laser weapon, and on the other hand, it can be interesting to know for example how missiles can be protected against laser weapons by using suitable construction materials or coatings.