<p>In this work, a novel plasmonic nano-absorber based on a stepped nanopillar array utilizing a metal–dielectric–metal (MDM) architecture is proposed. The design comprises a nickel (Ni) layer with periodic perforations, a dielectric spacer made of zinc oxide (ZnO (Postava)), and a Ni substrate reflective on the bottom. This multilayer configuration improves surface plasmon confinement and strengthens light–matter interactions across a broad solar spectrum. The stepped geometry and engineered perforation pattern support multiple optical resonances, including localized surface plasmon resonances (LSPRs), which together reduce reflectance and enable ultra-broadband absorption ranging from 400 to 3000 nm. The proposed absorber achieves an exceptional average absorption rate of 99.64%, outperforming many conventional counterparts. Due to its geometric symmetry, the structure exhibits polarization insensitivity (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\varphi = \varvec{0}~\text {to}~\varvec{90}^{\circ }$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>φ</mi> <mo>=</mo> <mrow> <mn mathvariant="bold">0</mn> </mrow> <mspace width="3.33333pt" /> <mtext>to</mtext> <mspace width="3.33333pt" /> <msup> <mrow> <mn mathvariant="bold">90</mn> </mrow> <mo>∘</mo> </msup> </mrow> </math></EquationSource> </InlineEquation>) and angular stability under oblique incidence (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\theta = \varvec{0}~\text {to}~\varvec{70}^{\circ }$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>θ</mi> <mo>=</mo> <mrow> <mn mathvariant="bold">0</mn> </mrow> <mspace width="3.33333pt" /> <mtext>to</mtext> <mspace width="3.33333pt" /> <msup> <mrow> <mn mathvariant="bold">70</mn> </mrow> <mo>∘</mo> </msup> </mrow> </math></EquationSource> </InlineEquation>). Extensive finite element simulations and analytical modeling confirm its superior optical performance and alignment with theoretical predictions. With its simplicity of fabrication, robust material, and high absorption efficiency, this Ni–ZnO–based stepped nanopillar array-based absorber presents a strong candidate for integration into solar energy systems, thermal imaging platforms, infrared stealth coatings, and multifunctional plasmonic devices.</p>

Stepped Nanopillar Array-Based Ultra-wideband, Wide Angle, and Polarization Insensitive Plasmonic Nano-absorber For Solar Energy Harvesting

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发表日期：

2025年9月20日

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Vinay Kumar,
Saurabh Kumar,
Sunil Kumar

摘要

In this work, a novel plasmonic nano-absorber based on a stepped nanopillar array utilizing a metal–dielectric–metal (MDM) architecture is proposed. The design comprises a nickel (Ni) layer with periodic perforations, a dielectric spacer made of zinc oxide (ZnO (Postava)), and a Ni substrate reflective on the bottom. This multilayer configuration improves surface plasmon confinement and strengthens light–matter interactions across a broad solar spectrum. The stepped geometry and engineered perforation pattern support multiple optical resonances, including localized surface plasmon resonances (LSPRs), which together reduce reflectance and enable ultra-broadband absorption ranging from 400 to 3000 nm. The proposed absorber achieves an exceptional average absorption rate of 99.64%, outperforming many conventional counterparts. Due to its geometric symmetry, the structure exhibits polarization insensitivity ( $\varphi = \varvec{0}~\text {to}~\varvec{90}^{\circ }$ $φ = 0 to 90^{\circ}$ ) and angular stability under oblique incidence ( $\theta = \varvec{0}~\text {to}~\varvec{70}^{\circ }$ $θ = 0 to 70^{\circ}$ ). Extensive finite element simulations and analytical modeling confirm its superior optical performance and alignment with theoretical predictions. With its simplicity of fabrication, robust material, and high absorption efficiency, this Ni–ZnO–based stepped nanopillar array-based absorber presents a strong candidate for integration into solar energy systems, thermal imaging platforms, infrared stealth coatings, and multifunctional plasmonic devices.