Transformation Optics,Graded IndexDevices And Applications

Transformation Optics has attracted many researcher’s attentions, since it was porposed to design an invisiblity cloaking in 2006. In recent years, the theory of Transformation Optics has been gradually improved. At the same time, more and more novel devices have been designed by Transformation Optics including invisible cloaking, optical black hole, optical illusion devices, beam reshapers, optical concentrators, polarization controllers. The theory of Transformation Optics has been extended to Transformation Thermodynamics and Transformation Acoustics. The study of Transformation Optics has set off a new wave of research.In this thesis we begin with the basic theory of Transformation Optics. We first drive the divergence and curl of a vector in an arbitrary coordinate system and then obtain the form of Maxwell’s equations in an arbitrary coordinate system. Based on the form-invariance of Maxwell’s equations and materials interpretation, we drive the basic formulas of Transformation Optics. After that, we designed some novel optical devices and some new devices for controlling DC magnetic field. We also made a further study on the performance of these devices based on the theory of Transformation Optics and numerical simulations.First we introduce how to design a radome to extend the scanning range of a phased arrary attenna by Transformation Optics. In practice, the scanning range of a phased arrary attenna is limited by many factors, we can extend the scanning angle of a phased arrary attenna by adding a special designed radome. The proposed radome can achieve a linear relationship between the angle of the input beam and the angle of the output beam. We also introduce the null-space medium to simplify the material requirement of the proposed radome:we only need two layered isotropic media to realize the proposed radome. Finally we use the numerical simulation to verify the performance of the proposed radome.We make an intensive study on the method to achieving invisibility cloak by using Transformation Optics. We propose a novel method to achieve invisibility cloak, namely, the scattering overlaping method. Different from the traditional method, our method has many advantages:First the concealed object can see the outside objects and the outside viewers cannot see the concealed object; Second even if the material or shape of the concealed object changes, our cloak still works; Third our cloak is passive, and we do not need to obtian the information of the detecting wave. This novel method will be likely used for the real invisibility in futrue.We also extend the theory of Transformation Optics to DC magnetic field:we can not only transform the distribution of DC magnetic field, but also transfrom magnets. We design many novel devices that can control the DC magnetic field including magnetic concentrator for achieving high DC magnetic field with high uniformity, magnetic lens to enhance DC magnetic field with high gradient, illusion devices for magnets and etc.We also study a novel lens based on graduated extremely low refractive index. This lens can achieve optical beam compression and collimation. We find that the output beam of this lens has very good directionility both in the near field and the far field. We have also designed some metal cylinderical structures to achieve such novel lens.Finally we summary this thesis and prospects. We also summary some related topics in our futrue research.