Numerical Insights into Wide-Angle, Phase-Controlled Optical Absorption in a Single-Layer Vanadium Dioxide Structure

Vanadium dioxide (VO<sub>2</sub>) is a well-known phase-change material that exhibits a thermally driven insulator-to-metal transition (IMT) near 68 °C, leading to significant changes in its electrical and optical properties. This transition is governed by structural modifications in the...

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Bibliographic Details
Main Authors: Abida Parveen, Ahsan Irshad, Deepika Tyagi, Mehboob Alam, Shakeel Ahmed, Keyu Tao, Zhengbiao Ouyang
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/15/5/450
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Summary:Vanadium dioxide (VO<sub>2</sub>) is a well-known phase-change material that exhibits a thermally driven insulator-to-metal transition (IMT) near 68 °C, leading to significant changes in its electrical and optical properties. This transition is governed by structural modifications in the VO<sub>2</sub> crystal lattice, enabling dynamic control over absorption, reflection, and transmission. Despite its promising tunability, VO<sub>2</sub>-based optical absorbers face challenges such as a narrow IMT temperature window, intrinsic optical losses, and fabrication complexities associated with multilayer designs. In this work, we propose and numerically investigate a single-layer VO<sub>2</sub>-based optical absorber for the visible spectrum using full-wave electromagnetic simulations. The proposed absorber achieves nearly 95% absorption at 25 °C (insulating phase), which drops below 5% at 80 °C (metallic phase), demonstrating exceptional optical tunability. This behavior is attributed to VO<sub>2</sub>’s high refractive index in the insulating state, which enhances resonant light trapping. Unlike conventional multilayer absorbers, our single-layer VO<sub>2</sub> design eliminates structural complexity, simplifying fabrication and reducing material costs. These findings highlight the potential of VO<sub>2</sub>-based crystalline materials for tunable and energy-efficient optical absorption, making them suitable for adaptive optics, smart windows, and optical switching applications. The numerical results presented in this study contribute to the ongoing development of crystal-based phase-transition materials for next-generation reconfigurable photonic and optoelectronic devices.
ISSN:2073-4352