Grooved High-Reflective Films for Ultraviolet Emission Enhancement

Conventional ultraviolet microplasma sources typically lack a back-reflection structure, resulting in radiative power loss from the backside. To enhance the emission efficiency of ultraviolet microplasma devices around 220 nm, we propose a multilayer reflective coating composed of alternating high-...

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Bibliographic Details
Main Authors: Hengrui Zhang, Zhanhua Huang, Lin Zhang
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Photonics
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Online Access:https://www.mdpi.com/2304-6732/12/7/644
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Summary:Conventional ultraviolet microplasma sources typically lack a back-reflection structure, resulting in radiative power loss from the backside. To enhance the emission efficiency of ultraviolet microplasma devices around 220 nm, we propose a multilayer reflective coating composed of alternating high- and low-refractive-index layers of Al<sub>2</sub>O<sub>3</sub> and SiO<sub>2</sub>, within a V-shaped groove. Key structural parameters, including the number of alternating film layer pairs, groove width, and light source position, are investigated to show their effects on ultraviolet reflection characteristics. The results show that reducing the groove width greatly enhances light reflection. When the groove width is 6.5 μm, the device exhibits a reflection efficiency of 47.82% and power enhancement of 91.66%, representing improvements of 2.5-fold and 4.2-fold, respectively, compared to non-optimized cases. Device performance is also influenced by the offset of the light source, which is more sensitive along the horizontal direction. This study provides a practical solution for developing high-efficiency ultraviolet emission devices.
ISSN:2304-6732