Precise control grows more regular alumina honeycomb templates for better optical resonators

What is it about?

Anodic alumina is an easy way to make tiny honeycombs that can be used as a template for optical resonators. Generally the holes in anodic alumina are somewhat random and elliptical, which we show degrades the performance of resonators made from metal. This article finds optimal conditions for making the template regular.

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Photo by Łukasz Nieścioruk on Unsplash

Photo by Łukasz Nieścioruk on Unsplash

Why is it important?

Metal nanoparticles absorb specific wavelengths of light - for example gold particles make a very rich red-coloured glass. These resonances are useful for a number of applications such as very sensitive detectors, but the particle shape has to be carefully controlled otherwise the resonances are blurred out. Particles can be easily produced from an anodic alumina template, but these are somewhat random. By controlling manufacturing conditions the template can be made more regular, which will improve the performance of resonators made this way.