Study On Band Gap Of Two-dimensional Photonic Quasicrystals With Multiple Complex Structures

The explosive development of information technology has brought about great changes in the human beings' life.This is due to the prosperity of semiconductor integrated circuits.However,when the size of integrated circuit(IC)is reduced to the physical limit,quantum effect will be caused,and the classical physics laws will no longer be applicable.The circuit chip with ultra-small size also has a variety of hidden dangers.So scientists began to focus on photons.The communication bandwidth and transmission rate are limited by the interaction between electrons and the quality of electrons.Since the interaction between photons is weak and the propagation speed of the light is fast,larger carrier bandwidth and data propagation rate can be gotten with photons.Analogous to semiconductor control electronics,photonic crystals(PCs)with photonic band gap(PBG)can control photons.So PCs are expected to be excellent candidates for micro-nano photon device and the basis of integrated optical circuit.Photonic quasicrystals(PQCs)have the following advantages: the low dielectric constant contrast when a complete PBG appears,higher isotropy of PBG and rich defect modes without introducing defect compared with periodic photonic crystals.PQCs have become the focus of research in recent years.The research on the band gap characteristics of PQCs is the basis of designing and fabricating photon devices.On the one hand,PQCs are more abundant than PCs,on the other hand,the complexity of PQC structure also brings some difficulties to the study.In this paper,the PBG characteristics are studied based on the PQCs generated by holographic interference.The main contents are as follows:1.The two dimensional 8-fold PQC's photonic band gap characteristics are optimized by changing the size and other structure parameters after constructing the structure.Firstly,8-fold PQC structure is constructed based on the holographic interference pattern.The influence of the structure size on the optical transmission characteristics is observed and the critical size of the quasicrystal is determined when the stable band gap is formed.Then,the influence of different dielectric arrangement on the optical transmission characteristics is observed.It is found that the structure of the air hole has strong localization to the light wave but the band gap is not obvious,and the structure of the dielectric rod can produce larger band gaps.Finally,the effects of the fill factor and the relative dielectric constant on the single band gap and the maximum band gap are studied respectively.It is found that the increase of fill factor or relative dielectric constant will make the band gaps more abundant under certain circumstances.These will lay the foundation for further research in this paper.2.The optimized quasicrystal structure is determined by studying the band gap characteristics after constructing several PQC structures.Firstly,two dimensional multiple quasicrystal structures including 8,10,12,14,18,22 and 26 PQCs are constructed based on the holographic interference pattern.Since both fill factor and relative dielectric constant affect the formation of band gap,the maximum band gaps of these quasicrystal structures under different fill factors are calculated according to the same simulation settings.On the basis,by comparing the maximum band gap that each quasicrystal structure can generate at different relative dielectric constant,it is found that the 10-fold PQC produced by five beams interference shows better ability in band gap generation.The root reason is that the self-similarity of this structure is higher.In addition,the electromagnetic field distribution of different quasicrystal structures inside and outside the band gap is given,which further verifies the accuracy and rationality of the study.