Design and Fabrication of Dual-Scale Broadband Antireflective Structures on Metal Surfaces by Using Nanosecond and Femtosecond Lasers

Abstract

Antireflective surfaces, with their great potential applications, have attracted tremendous attention and have been the subject of extensive research in recent years. However, due to the significant optical impedance mismatch between a metal surface and free space, it is still a challenging issue to realize ultralow reflectance on a metal surface. To address this issue, we propose a two-step strategy for constructing antireflective structures on a Ti-6Al-4V (TC4) surface using nanosecond and femtosecond pulsed lasers in combination. By controlling the parameters of the nanosecond laser, microgrooves are first scratched on the TC4 surface to reduce the interface reflection. Then, the femtosecond laser is focused onto the sample surface with orthogonal scanning to induce deep air holes and nanoscale structures, which effectively enhances the broadband absorption. The antireflection mechanism of the dual-scale structures is discussed regarding morphological characterization and hemispherical reflectance measurements. Finally, the modified sample surface covered with micro-nano hybrid structures is characterized by an average reflectance of 3.1% over the wavelengths ranging from 250 nm to 2250 nm.

Biomimicry in nanotechnology: a comprehensive review

“…Such biomimetic anti-reflective transparent materials have a pervasive application including display, solar windows, optical components, and devices [188][189][190][191][192][193][194][195] . Single-step laser texturing approach, nanosecond, and femtosecond laser processing systems are used to fabricate such anti-reflective transparent structures 78,196,197 .…”

“…188–195 A single-step laser texturing approach, and nanosecond, and femtosecond laser processing systems are used to fabricate such anti-reflective transparent structures. 78,196,197…”

“…[188][189][190][191][192][193][194][195] A single-step laser texturing approach, and nanosecond, and femtosecond laser processing systems are used to fabricate such anti-reective transparent structures. 78,196,197 7 Biomimetic nanotechnology in textile engineering…”

Thermal-Assisted Laser Fabrication of Broadband Ultralow Reflectance Surface by Combining Marangoni Flow with In Situ Deposition

“…The average reflectance of the sample in the wavelength range of 500–1000 nm is stable below 6%, and the static contact angle of the sample reaches 150° [ 22 ]. Some researchers adopted two-step laser processing to achieve low reflectance surface [ 23 , 24 , 25 ]. Cheng et al combined nanosecond and femtosecond pulse lasers to prepare TC4 surface with an average reflectance of 3.1% in the wavelength range of 250–2300 nm [ 25 ].…”

Ultra-Low-Reflective, Self-Cleaning Surface by Fabrication Dual-Scale Hierarchical Optical Structures on Silicon

“…In particular, the fabrication of micro-nano structures on the silicon surface is a popular route for surface modification [14][15][16][17][18][19][20][21]. For example, pyramidal structures effectively reduce the surface's reflectivity and improve the efficiency of photovoltaic cells, which is attributed to their ability to collect and capture light through internal reflection [22][23][24][25][26][27][28][29][30].…”