What is it about?

We fabricate Ag/a-Si multilayer hyperbolic metamaterials by magnetron sputtering. Using disorder as a design parameter, our structures show near-perfect absorption, and this feature persists when heated to up to 300C. We study the stability limits and find that the instability at higher temperatures is driven by strain originating in the thermal expansion coefficient mismatch.

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Why is it important?

Many proposed applications of hyperbolic metamaterials require thermal stability, such as thermophotovoltaics of hyperthermia. However, metamaterials derive their properties from their structure, and the structure of composite materials is known to degrade at elevated temperatures. Here, we show a method to identify the driving force of the degradation and explore how to design structures with higher thermal stability.


Our results could help design metamaterials (in this case, leading to near-perfect absorption) that can withstand high temperatures, which is vital in the energy field.

Jose Luis Ocana Pujol
ETH Zürich, D-CHAB

Read the Original

This page is a summary of: Strain‐Driven Thermal and Optical Instability in Silver/Amorphous‐Silicon Hyperbolic Metamaterials, Advanced Optical Materials, October 2022, Wiley,
DOI: 10.1002/adom.202201749.
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