Cupric Oxide Mie Resonators

In the past two decades, plasmonic Mie resonators enabled numerous breakthroughs in the manipulation of light at the subwavelength scale as well as at larger scales through the construction of metamaterials/surfaces from them, as artificial atoms. Central to these features are enhanced field concentrations and extinction cross sections at Mie resonances. These unique aspects are also exhibited by moderate-to-high refractive index dielectric Mie resonators. Dielectric Mie resonators offer further unique attributes, such as magnetic resonances and low losses. Here, we report on submicron cupric oxide (CuO) particles with a medium refractive index that can exhibit strong electric and magnetic Mie resonances with extinction/scattering cross sections as large as those of plasmonic resonators. Through the development of particle synthesis techniques enabling shape and size control, optical spectroscopy, and finite-difference-time-domain simulations, we show the Mie resonance wavelengths are size- and shape-dependent. This spectral tunability in the visible-to-near-infrared regions allows for energy harvesting and light manipulation in a wider range of the solar spectrum. The strong electric and magnetic Mie-resonance-mediated nanoantenna attribute of CuO particles can be potentially exploited in applications, such as metamaterials/surfaces, photocatalysis, and photovoltaics.