Polarization- and angle-insensitive ultrabroadband perfect metamaterial absorber for thermophotovoltaics

We report an ultrabroadband perfect metamaterial absorber, comprising a two-dimensional array of a hemi-ellipsoid shaped metallo-dielectric multilayered structure. What we believe, to the best of our knowledge, is an unprecedented average absorbance of similar to 99% is theoretically demonstrated in the 300 to 4500 nm spectral range at normal incidence. We use 20 pairs of molybdenum-germanium metallo-dielectric layers with tungsten as the ground metal placed on a silicon substrate. Our design is polarization-independent as well as angle-insensitive (up to 60 degrees), making it a perfect superabsorber. Theoretical modeling based on effective medium theory validates our full-wave simulation results. The figure-of-merit calculations suggest that our superabsorber can outperform recently reported broadband absorbers. The proposed design has potential application in thermophotovoltaics for solar energy harvesting. (C) 2021 Optical Society of America

Automated summary

The study presents an ultrabroadband perfect metamaterial absorber with an unprecedented average absorbance of around 99% in the 300 to 4500 nm spectral range. The design is polarization-independent and angle-insensitive, making it a potential candidate for thermophotovoltaics in solar energy harvesting.