Study On Characteristic And Application Of The Graded-Index Photonic Crystal Concentrators And Absorders

Light absorber has a great prospect for development in the field of non-imaging device’s research and application, such as mobile photovoltaic cells, multi-color infrared sensor and stealth technology of image device. The grid guides structure and resonant structure are used extensively in traditional light absorber, where the additional excitation source should be loaded and only TE wave can be absorbed efficiently. Light absorber using gradient photonic crystals have both greater control of beam and higher abosorption efficiency than traditional one, as well as many other advanteges, such as simplicity in design, low loss, small size and wide appliction areas.There could be gradient change in the material’s macroscopic properties by controlling the PC’s(Photonic crystal) parameters, which is a mian method to get GRIN PC(Graded-index photonic crystal). As a new type of PC, GRIN PC has remarkable ability in controlling of the electromagnetic field. Nowadays, the structures of available light absorber unit employing GRIN PC are mostly circular and spherical. In order to improve wide angle light absorber’s flexibility in design,omnidirectional elliptical light absorber was put forward firstly by Ludmila Prokopeva and Alexander Kildishev with the methods of ray tracing and full wave simulation. However, the theoretical analysis and practical application in this field of research work is not yet perfect.In this paper, a two dimensional omnidirectional elliptical light absorber based on GRINPC’s structure was proposed by studying on a proper sunflower shaped array round light absorber unit to achieve the goals of shape diversification and absorption efficiency improvement.Main work in this article is as follows:1 The research direction of the graded-index photonic crystals and the current research trends were introduced, besides, the research process in light absorber field was introduced mainly.2 The theoretical foundation of the GRIN PC research, such as energy band structure of crystals, calculation of effective parameters and relevant research technique were presented. Effective medium theory and finite difference time domain method of GRIN PC were explained in detail. The photonic crystal band structure involved in this work had been simulated.3 The research and design of GRIN PC’s light absorber based on rectangular array was described briefly. The design of light absorber utilizing triangular array and six times sunflower shaped array was expounded. The performance of this structure was analyzed.The absorbing quality of TE light absorber using six times sunflower shaped array was improved by optimizing the structure.4 The transmission behavior of light in graded index material under elliptic coordinate system was studied. The design of light absorber applying rectangle array was expounded. The performance and spatial sensitivity were analyzed. The reasons of these phenomenon was interpreted. The influence of different parameters on the absorption performance of this structure unit was described briefly.