Metastructure-inspired ultraviolet and blue light filter

Currently, many studies are being conducted to apply optical metamaterials to the transmittance control of visible light and near infrared wavelengths. In this study, a metastructure was fabricated with periodic metal holes that can reduce the transmittance of only ultraviolet (UV) and blue light in the wavelength band from UV to visible light. The connection structure of the metal-hole-patterns, with a hole size of tens to hundreds of μm, and the crystallinity of the metal could be controlled through the three-step process of polystyrene (PS) nanosphere array formation, using the air–water interface method, and size adjustment of the PS nanosphere, through the etching process, and through the adjustment of the metal film thickness. The glass substrate, with an Al-hole-patterned metastructure (an Al-hole-pattern size of ∼245 nm and an Al thickness of ∼60 nm), showed a low transmittance of 33% and 28% in the wavelength bands of 350 nm and 470 nm, respectively, and a high transmittance of 67% and 57% in the ranges of 540 nm and 670 nm, respectively, owing to the metacharacteristics manifested in periodically connected metal patterning structures. This Al-hole-patterned metastructure is expected to be applicable to various optical devices that require a reduction in the transmittance of only the UV and blue light wavelength band.