Resonance-free ultraviolet metaoptics via photon nanosieves.

Ultraviolet (UV) light with high-energy photons is widely used in various areas such as nano-lithography, biology, and photoemission spectroscopy. The flexible control over its amplitude and phase is a longstanding problem due to the strong absorption from most materials. Here, we propose a nano-aperture platform to control the amplitude and phase of UV light and experimentally demonstrate amplitude- and phase-type holograms at a wavelength of 355 nm. In principle, nano-apertures etched on a metal film can be filled in vacuum, so that the material issue about optical absorption is not involved in this configuration, allowing us to manipulate UV light through the geometry of nano-apertures even when plasmonic resonances are absent. A binary-amplitude nanosieve is used to reconstruct three holographic images at different cut-planes by tuning the constructive interference elaborately. Meanwhile, rectangular nano-apertures are employed to demonstrate UV holograms with geometric phase that is controlled by the orientation of the nano-apertures. This platform could be extended to other UV regions.