Enhanced Absorptance of 45# Steel by Laser-Induced Periodic Surface Structures (LIPSS)

Abstract

The absorptance of metals is often low within the visible and near-infrared band at room temperature. Increasing the absorption of metals plays a vital role in reducing energy consumption and production cost. After irradiation by 10 ns linearly polarized pulses with fluence close to the zero-probability damage threshold, the surface of 45# steel samples exhibited four kinds of surface structures in the spot area. The samples’ absorptance is improved by 38% when a high-quality laser-induced surface structure (LIPSS) appears at the spot centre. With the increase of the number of pulses, LIPSS begin to melt down, which will decrease the surface absorptance due to the appearance of damage stripes. The relative absorptance of samples was measured by an integrating sphere system. The paper reports detailed experiments to show that LIPSS can improve samples’ absorptance significantly.