Fabrication of antireflection micro/nanostructures on the surface of aluminum alloy by femtosecond laser

Abstract

Designed micro‐nano structures on the surface of aluminum alloy provide excellent light trapping properties that can be used extensively in thermal photovoltaics, sensors, etc. However, the fabrication of high‐performance antireflective micro‐nano structures on aluminum alloy is chal-lenging because aluminum has shallow intrinsic losses and weak absorption. A two‐step strategy is proposed for fabricating broadband antireflection structures by superimposing nanostructures onto microscale structures. By optimizing the processing parameters of femtosecond laser, the average reflectances of 2.6% within the visible spectral region (400–800 nm) and 5.14% within the Vis‐NIR spectral region (400–2500 nm) are obtained.