Controlling Of Light Dynamics In Non-hermitian And Topological Photonic Lattice

In the realm of photonics,light wave controlling is a subject of modulating the polarization,frequency,spatial distribution and dispersion of light by different means including electrooptic effect,acousto-optics effect and magneto-optics effect.With the development of nano technology,it is possible to control the light wave using nano photonic devices,which plays a significant role in the field of optical communications,optical integration and quantum computations.This thesis,combining with quantum mechanics,topology physics,and solid state physics,systematically studies the non-Hermitian light wave dynamics and the topologically protected edge state in the open optical systems and topological photonics,respectively.Corresponding works explore the novel methods and theories to realize the controlling of the spatial distribution and diffraction of light wave.The specific research contents are as follows:In the first chapter,the basic concepts of non-Hermitian photonics and topological photonics are introduced,and corresponding phenomena are also included.In the second chapter,we study the three-layered photonics lattice with parity-time symmetric perturbations.We investigate effective Hamiltonian for the main waveguides,and calculate the dispersion relations.We further explore the mode distribution and focus on the controlling of asymmetric spatial distribution of light wave in the system.The result provides a novel idea for all-optical switches.In the third chapter,we demonstrate that the Hermiticity can be modulated by the judicious design of a system.Based on the quantum mechanics and solid state physics,the light propagation mechanism is established.We further calculate the dispersion relations and the corresponding group velocity distributions.The numerical results show that such a Hermiticitytunable photonics lattice can realize bi-directional group velocity controlling,namely,accelerate and decelerate group velocity in the same system.Dynamic localization and asymmetric transmission of light wave are also observed.Our work brings a new idea for controlling the light pulse in the temporal domain,and has potential application in optical communications and sensing.In chapter four,a novel quasi-one-dimensional photonics lattice is proposed.Based on the topological and quantum theories,this thesis investigates the conditions required to realize topologically protected edge state,and further achieve an asymmetrically localized near-zero mode.This result enriches the concept of topological photonics and may have potential application in the future quantum computation.In chapter five,the conclusion and the prospect of this thesis are presented.We summarized the main projects and innovation points in the thesis.Lastly,suggestions for further study are proposed.