Nano-structured efficient meta-absorber for optical applications: solar thermophotovoltaic and solar sail

Abstract Metamaterials can significantly boost solar cell efficiency, enhance energy harvesting technologies, and advance more efficient spacecraft propulsion systems. Meta-absorbers that collect solar energy require high-temperature stable materials that withstand the rising temperatures of the sun’s intense solar radiation. However, achieving high bandwidth with high-temperature-stable materials and in a simplified three-layer configuration remains a significant research gap. To address the challenge of achieving high bandwidth with refractory materials, this study presents a simple three-layer metamaterial absorber (MMA) composed of tungsten and silicon dioxide, achieving an excellent absorption value of 97.36% across the visible and infrared ranges. The absorber achieves a stable absorption over 90% from 390 to 970 nm, covering a bandwidth of 580 nm, and exhibits complete insensitivity to polarization angles in both TE and TM modes. A low polarization conversion ratio (PCR) and the analysis of co-polarization and cross-polarization confirm the polarization-insensitive nature of the absorber. The PCR represents its effectiveness as an absorber rather than a polarization converter. Localized surface plasmon resonance (LSPR) is more intense at shorter wavelengths, leading to concentrated electric and magnetic resonances that enhance wave absorption within the electric and magnetic field distributions. Conversely, propagating surface plasmon resonance (PSPR) becomes more significant at longer wavelengths, as reflected in the field patterns of the proposed metasurface. Additionally, the MMA achieves an outstanding thermal conversion efficiency of 97.2% for solar energy at an operating temperature of 573 K, demonstrating its effectiveness as a solar absorber. This research is significant in the development of a highly simplified and high-performance optical harvester that bridges the gap between theoretical plasmonics and practical high-temperature applications. Along with the potential application as a solar energy harvester, the absorber finds its potential use in space exploration, where it could be utilized it as a solar sail for spacecraft.