Large‐Scale Laser Nanopatterning of Multiband Tunable Mid‐Infrared Metasurface Absorber. Issue 22 (18th August 2022)

• Record Type: Journal Article
• Authors: Yuan, Dandan; Li, Jun; Huang, Jiaxu; Wang, Min; Xu, Shaolin; Wang, Xinwei
• Is Part Of: Advanced optical materials. Volume 10:Issue 22(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-18
• Subjects: large‐scale nanopatterning -- metasurfaces -- mid‐infrared absorption -- phase‐change materials -- separate pulse laser ablation; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202200939
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Large‐scale nanopatterning at low cost and high throughput is crucial to the practical applications of metasurfaces. Phase‐change materials equipped in these metasurfaces as modulation layers or resonators are generally applied to achieve a tunable function and have attracted significant attention. Here, an efficient method is developed by combining ultrafast laser localized modification/ablation and subsequent etching to fabricate nanostructures on a phase‐change material, Ge2 Sb2 Te5 (GST), over a wafer‐sized area. The localized laser treatments under gradually increased laser fluences contribute to the variety of achievable nanostructures including disk and ring structures, whose feature sizes and periods can be tuned by adjusting laser parameters and subsequent etching conditions. A mid‐infrared metasurface absorber is designed and fabricated by using the GST ring units as resonators. Notably, varying the geometrical features of rings allows generating dual‐band and tri‐band absorption peaks in the mid‐infrared spectral range, whose peak absorptivity can reach ≈92%. By converting GST from amorphous to crystalline state, a broad absorption spectral redshift of 700 nm is achieved. The large‐area high‐throughput fabrication together with high‐absorption design demonstrates their potential in mass production of phase‐change metasurface‐based absorbers. Abstract : By combining laser localized modification/ablation and subsequent etching, a wafer‐scale nanostructure array is fabricated on a phase‐change material [Ge2 Sb2 Te5 (GST)]. The morphology can be tuned to be disks and rings with different geometrical features by modulating laser fluence. Numerical simulation and experimental results prove that the GST ring based metasurface sustains significant multiband tunable absorption in the mid‐infrared spectrum.