High-Efficiency Ultra-Violet Dielectric Meta-Holograms with Antiferromagnetic Resonances

TL;DR

This paper presents a high-efficiency ultraviolet meta-hologram using niobium pentoxide, leveraging antiferromagnetic resonances to achieve 81% efficiency at 355nm, advancing UV nanophotonics and meta-optics.

Contribution

Introduction of a novel UV meta-hologram design utilizing antiferromagnetic resonances in Nb2O5 to achieve high efficiency and polarization control.

Findings

Achieved 81% efficiency at 355nm wavelength.

Utilized high-aspect-ratio nano-bricks to excite antiferromagnetic resonances.

Demonstrated polarization conversion via antiparallel magnetic dipoles.

Abstract

Metasurfaces with spatially varying subwavelength structures enable full control of electromagnetic waves over a wide spectrum. High-efficiency metasurfaces, especially in a transmission mode, are of practical significance in optical elements and systems, hitherto their operating frequencies have been expanded down to visible-wavelength ranges. Challenges of developing shorter-wavelength metasurfaces originate from electromagnetic loss caused by strong absorption for most high-refractive-index materials. Here we introduce a large-bandgap semiconductor material-niobium pentoxide (Nb2O5)-to engineer a ultraviolet meta-hologram with a total efficiency of 81% at 355nm wavelength. This meta-hologram modulates the geometric phase of transmitted circular-polarization light via orientation-varying high-aspect-ratio nano-bricks that are elaborately designed to excite antiferromagnetic resonances. We reveal that the induced antiferromagnetic modes maintain one component (e.g., Ex-component) of incident light through even-numbered antiparallel magnetic dipoles (AMDs) but reverse the other component (e.g., Ey-component) via odd-numbered AMDs, thus realizing high-efficiency polarization conversion. Our approach might open the door towards high-performance ultraviolet-light nanophotonics and meta-optics.