The Research Of Negative Refraction In Two-Demensional Chiral Photonic Crystal

Recently, as an artificial photonic device with excellent performances, photonic crystal (PC) has been found promising application in many fields, e.g., optical communication, which arouse intensive interests. For their special optical properties, the chiral materials are also one of the hot spots in international academe. Particularly, the investigation of chiral photonics devices has caught many researchers'attention.In this thesis, the negative refraction in two-dimensional chiral photonic crystals has been studied based on planewave expansion (PWE) method and finite difference time domain (FDTD) . First, the reserch on the photonic crystals and chiral media was reviewed, the background and significance of the issues were discussed. The chirality were classified conceptually and the current situation of development and evolution of the definition are briefly described for the dielectric chirality and structural chirality.To apply the common numerical methods to calculating chiral photonic crystals, the constitutive equation for bi-isotropic chiral medium has been studied in detail. As in the chiral medium the engen modes are left and right circularly polarized (LCP and RCP) light, the chiral discrete equations which adapted to the FDTD method has been derived for left and right circularly polarized decomposition, the chiral plane wave expansion method has been described at the same time.Bandgap structure of two-dimensional chiral photonic has been studied by using planewave expansion method, the conditions for negative refraction in two-dimensional photonic crystals has been obtained through simulation. Correspondingly, the band structures for the left and right circularly polarized light are calculated respectively in the square and triangular lattice. The effect of the chiral parameters on separation of the band gap and formation of the complete forbidden band are also discussed deeply.Finally, the FDTD method was used to simulate the negative refraction for the two-dimensional chiral and achiral photonic crystals, the effect of chiral medium on the LCP light and RCP light also been discussed.