Optical Analysis and Optimization of Micropyramid Texture for Thermal Radiation Control

Abstract

ABSTRACT While anti-reflective properties of pyramid texture are widely used, their use for thermal radiation control has received relatively little attention and the understanding of geometric parameters for design optimization is not well established. Here we use finite-difference time-domain simulations in conjunction with an algorithm to optimize thermal characteristics of micropyramid-textured metallic, ceramic, and polymer materials. Our simulations indicate that the pyramid height-to-base ratio is an effective parameter in developing an engineered thermal response. For nickel, the micropyramids with 2–4 height-to-base ratios over 0.5–4 µm base spans provide near-perfect absorption in 300–2500 nm wavelengths. The electric field analysis shows the optical properties are driven by the effects of localized resonance and field confinement. Our thermal cost function-based optimization has led to micropyramid texture that can have a significant impact on heating or cooling such as the solar absorption increase in nickel from 337 to 982 W/m2, the thermal emission increase in alumina from 106 to 170 W/m2, and the thermal emission increase in PDMS from 160 to 172 W/m2. This work not only provides the understanding of micropyramid properties for thermal radiation control but also presents an algorithmic process that could be used for efficient optical-thermal optimization of geometries beyond micropyramids.