Preparation And Study Of Photonic Crystals Based On Nanoporous Anodic Alumina

Photonic crystals(PCs),as a kind of new material which can control photons,have great potential and application value in optics and optoelectronics.In the past decade,corresponding theories and preparation methods have been established.Among them,porous anodic alumina photonic crystals(NAA-PCs)have some favorable properties such as simple preparation method,cheap materials orderly structure,easy and diversified adjustment of the photonic band gap,which is more and more popular among researchers.In this paper,NAAPCs with different morphologies were prepared by anodization.The structure and morphology of NAA-PCs were analyzed in detail,and the method of controlling the position of photonic forbidden band was given.Two-step anodization can greatly improve the order of NAA.In this paper,the traditional two-step anodization was adjusted experimentally to analyze the effect of the first anodization conditions on the preparation of NAA template.It is found that when the first anodization is different from the second anodization,there are two different kinds of pores on the surface: the interpore distance is 100 nm and 270 nm respectively.And the difference in structure becomes smaller and smaller as the experimental time prolongs.Based on the method of the above two-step anodization,we changed the process of preparing NAA layered photonic crystals,and increased the anodization voltage to more than 150 V in oxalic acid electrolyte.It is found that there exists not only the interpore distance up to 400 nm at the bottom of NAA,but also the NAA-PCs which can display color directly on aluminum substrate under this method.The photonic forbidden band can be changed rapidly by adjusting the voltage and time of anodization.And the law of the shift of the forbidden band is given by combining Looyenga–Landau– Lifshitz(LLL)model with the experimental results.Then we obtain that the key factor affecting the photonic forbidden band is the current density through detailed analysis of the reaction process,thus the method of obtaining uniform photonic forbidden band is given.Based on the finite-difference time-domain method,NAA-PCs which can be colored on aluminum substrate were simulated and analyzed.And compared with ordinary PCs,we found that the colored NAA-PCs on aluminum substrate are also capable of sensing and have a certain performance improvement.In addition,the factors affecting the sensitivity of NAA sensor are analyzed by using the fixed variable method,and the specific scheme to optimize the performance of NAA sensor is given.This paper has a certain guiding significance for the study of NAA in aluminum or aluminum alloy coloring and sensor application.