Reconfigurable Switches and Color Pixels Based on Metal-Hydrides Systems

Adaptive and reconfigurable photonic devices are critical to a variety of applications from photonic circuits and color pixels to computing and quantum information processing. One promising class of materials are metal-hydrides, which can undergo extreme changes in optical properties via insertion of hydrogen atoms into the metallic lattice, which can be controlled through applied bias or gas pressure. Here we present our recent work on developing reconfigurable optical devices based on switchable metal-hydrides. In addition to optical, mechanical, and chemical characterization [1], we have developed vivid color pixels with wavelength shifts (&gt;100 nm) during hydrogenation of various materials. Through appropriate design, we have produced structures that have five orders of magnitude change in reflectivity, as well as systems for physical encryption and counterfeit detection. We find alloying of these metal films not only improves cyclability, but also leads to higher hydrogen fractions than previously obtained as a result of film stresses and microstructuring [2]. Finally, we will show how novel optical substrates can enhance these effects [3] and how nanostructuring can lead to additional opportunities for adaptive systems with tunable optical behavior.<br/><br/>[1] KJ Palm, et al., <i>ACS Photonics</i>, <b>5</b>, 4677–4686 (2018)<br/>[2] KJ Palm, et al., <i>ACS applied materials & interfaces</i> <b>11</b>, 45057-45067 (2019)<br/>[3] KJ Palm, et al., <i>Optics Express</i> <b>30</b>, 21977-21989 (2022)