Selective etching properties of Mg thin films and micro/nanostructures for dynamic photonics [Invited]

The fixed post-manufacturing properties of metal-based photonic devices impose limitations on their adoption in dynamic photonics. Modulation approaches currently available (e.g. mechanical stressing or electrical biasing) tend to render the process cumbersome or energy-inefficient. Here we demonstrate the promise of utilizing magnesium (Mg) in achieving optical tuning in a simple and controllable manner: etching in water. We revealed an evident etch rate modulation with the control of temperature and structural dimensionality. Further, our numerical calculations demonstrate the substantial tuning range of optical resonances spanning the entire visible frequency range with the etching-induced size reduction of several archetypal plasmonic nanostructures. Our work will help to guide the rational design and fabrication of bio-degradable photonic devices with easily tunable optical responses and minimal power footprint. (c) 2021 of America under the terms of the OSA Access

Automated summary

This study demonstrates the potential of utilizing magnesium for optical tuning through etching in water, with modulation of etch rate by controlling temperature and structural dimensionality, and substantial tuning range of optical resonances across the visible frequency range.