Electromagnetic Characterization of a Wideband Nanoscale Metamaterial Absorber for Ultraviolet Radiation Shielding

In this article, a new metamaterial absorber (MMA) structure is presented with the nanoscale feature that operates in the ultraviolet frequency spectrum. The presented MMA is constructed on a Silicon (Si) substrate where Gold (Au) is used as the resonator as well as the backplane. The overall structural dimension of the proposed MMA cell is 0.1λ_max × 0.1λ_max, where λ_max represents the maximum wavelength at a lower cut-off frequency of 750 THz. The newly designed resonating patch provides an average absorption of 85% within a bandwidth of 750 THz to 900 THz with a peak absorption of above 99%. The absorption scenario is stable up to 90° for incident and polarization angle variations. Moreover, the proposed MMA exhibits almost zero polarization conversion ratio (PCR) and provides similar absorption spectra considering co and cross-polarized radiations. The MMA exhibits a good shielding effectiveness of 34.27 dB (maximum) which makes it effective for shielding ultraviolet (UV) radiation. As the design has a wide bandwidth of absorption and a near unity absorption, this compact and stable metamaterial absorber can be suitable for many applications such as for radiation shielding to avoid the harmful effects of ultraviolet radiation on living bodies, air, and water purification by leveraging germicidal characteristics of UV radiation, increasing efficiency of solar devices incorporating UV light absorption.