High efficiency glass-based VUV metasurfaces

TL;DR

This paper reports the first transmissive VUV metalens at 175 nm, achieving high diffraction efficiency using UV-grade silica, opening new possibilities for compact VUV optical systems.

Contribution

It introduces the first transmissive VUV metalens at 175 nm, overcoming material and fabrication challenges for short-wavelength metasurfaces.

Findings

Achieved an average diffraction efficiency of 53.3% at 175 nm.

Used UV-grade silica to enable VUV transparency.

Demonstrated a large NA (0.5) metalens for VUV wavelengths.

Abstract

Most advances in metaoptics have been made at visible wavelengths and above; in contrast, the vacuum ultraviolet (VUV) has barely been explored despite numerous scientific and technological opportunities. Creating metaoptic elements at this short wavelength is challenging due to the scarcity of VUV transparent materials and the small sizes of the required nanostructures. Here, we present the first transmissive VUV (175 nm) metalens. By using UV-grade silica and trading-off the Nyquist requirement for subwavelength structures against feasibility of the fabrication process, we achieve a step-change in diffraction efficiencies for wavelengths shorter than 300 nm. Our large numerical aperture (NA = 0.5) metalens shows an average diffraction efficiency of (53.3 +- 1.4)%. This demonstration opens up new avenues for compact flat optic systems operating in the VUV range.