Confinement of ultraviolet light using lattice modes in Al and Si nanocylinder arrays

Silicon (Si) nanostructures are emerging in the fields of metasurfaces and nanophotonics, while aluminum (Al) is a plasmonic material that is active in the ultraviolet (UV) region. While Si is active in the visible range, its performance in the UV region is not well understood. Here, we discuss our experimental results of the confinement effect in the UV region of Si and Al nanostructures. We prepared Si and Al nanocylinder arrays with a periodicity in the UV range, so that UV light is diffracted coherently and trapped in the plane of the array. We deposited a UV absorbing film on top of the arrays and examined the UV confinement effect by measuring the photoluminescence (PL) intensity from the film. The PL intensity from the film on the Al nanocylinder array was found to be higher than it was from the Si array, showing that the confinement effect is more pronounced in the Al array in the UV region. The result is useful for selecting a constituent material when fabricating nanostructures that are active at specific wavelengths.