Theoretical Approach to Simulate Efficient Selective Solar Absorbers With Micro or Nano Structured Arrays

Numerical calculations based on rigorous coupled-wave analysis were performed to determine the absorptance of the photonic crystal surface on the absorber. The effect of nano geometry of the photonic crystal in tungsten on the selectivity of the absorber was investigated first, including period (L), aperture (A) and depth (d).

A design algorithm for the photonic crystal heat absorbing surface was summarized. Based on the results, a design with combined large and small square patterns was proposed to improve the absorptance, which demonstrated the ability to broaden the absorbing band by mix-period nano patterns. Integration of an anti-reflection coating (ARC) on the photonic crystal using aluminum oxide (Al2O3) was also studied.