On the use of the Perlin noise function to calculate the laser absorption coefficient by rough surfaces

Surface roughness influences absorption of a laser beam from a metallic surface. Generation of surfaces with realistic surface roughness remains an active area of research and multiple methods have been examined with varied success. Here Perlin noise is implemented in order to model surface morphology and laser absorption with the Fresnel equations is studied. Copper surfaces with Ra ranging between 10 μm to 250 μm are simulated and it was found that the surface absorption was proportional to the surface roughness. Another significant factor is the angle at which the laser beam hits the surface. Incident angles, ranging between -1.47 rad (-60°) to 1.47 rad (60°), are studied and it was revealed that right angles resulted in the highest absorption. Finally, a second-order polynomial model that accurately fits the surface roughness and absorption coefficient is suggested. In summary, evidence for the utility of the Perlin noise function in modeling laser absorption by a metallic surface is provided.