Numerical Research On Thermal Radiative Properties Of One-Dimensional Periodic Microstructured Surface

Micro/Nano scale radiation is quite different from the traditional macro scale thermal radiation. Some new features of radiation transmission process could be exhibited once the scales of structures are very close to the wavelength of thermal radiation when we study on a certain radiation problem. By considering that the essence of thermal radiation is a kind of electromagnetic wave, electromagnetic theory can be used to describe the relationships and fluctuation characteristics of the electromagnetic field components. Thus, radiation transmission characteristics of periodic microstructures could be reasonably simulated and explained by numerical methods based on Maxwell equations.In this work, visible and near-infrared thermal radiative properties of 1D periodic microstructures were analyzed by using Finite Differnece Time Domain(FDTD) and Plane Wave Expansion(PWE) numerical methods. Characteristics of the reflectivity curve and its influence factors including periodic number, refractive index, optical thickness and the incident angle were discussed. Morevoer, reflection characteristics of the micro scaled structure which was built by adding metal nano-layer in 1D photonic crystal were studied. By analyzing the influence of periodic number and the thickness of metal layer, we found that thin silver layer could make 1D photonic crystals exhibit obvious band gap under a very small periodic number, and the width of band gap could becomes adjustable due to the variation of the thickness of the metal layer.In order to control the transmission characteristics of 1D periodic microstructures, an air-slit splited 1D photonic crystal was studied, then, one kind of periodic blocks were employed to enhance the transmission. By analyzing the relationship of selective transmission and the structure parameters, the proposed periodic microstructures could achieve selective high transmission in the band gap of 1D photonic crystal.Based on the study with the reflection characteristics in this work, a Morpho butterfly liked periodic microstructure was built. The structures color of Morpho butterfly was analyzed and explained originated from the simulated results. Meanwhile, the influence of structure parametes and the refractive index of environment were discussed.