Octagonal flower-shaped wideband polarization insensitive metamaterial absorber for solar harvesting application

Metamaterial absorbers (MMA) attract great interest due to their unique properties. For energy harvesting from solar MMA in the optical region having wide bandwidth is one of the top research sectors nowadays. Our main solar source is the sun which includes UV, NIR and visible wavelength. Among them, the visible wavelength is most important for harnessing energy. Absorber operating in this region has a variety of application fields. In this study, the process of achieving a high absorption rate for total solar visible wavelength is being proposed. Various properties of the proposed MMA have also been analyzed to comprehend its characteristics. Geometric analysis was performed to optimize the design and output characteristics for optimal value and probable application. Cross and co-polarization, along with PCR (Polarization Conversion Ratio) verification, were also evaluated. The proposed MMA operates for full visible wavelength spanning 380 nm to 700 nm. It has an absorption rate of 97.8% and peak absorption of 99.9%. An above 90.8% absorption level was achieved throughout the operating wavelength. Furthermore, this absorber is totally polarization insensitive and the incident angle is independent up to 70 degrees. A comprehensive parametric assessment has been conducted to accurately characterize the absorber and understand how the results are derived. Finite Integration Technique (FIT) has been employed for calculating absorbance and reflectance. The proposed model shows similar absorbance across TEM, TE, and TM waveguide propagation modes. Furthermore, the constancy of the polarization angle has been validated. Because of the excellent metamaterial properties, the proposed metamaterial absorber can be used for optical range, solar harvesting, solar cell, and solar thermophotovoltaic (STPV) applications. It can be used for light-detecting and sensing applications as well.