Information Wave Field Control Based On Topological Properties Of Metamaterials

Wave is one of the important carriers of information transmission and plays an important role in the application of information and communication technology.The exploration of the physical characteristics and transmission characteristics of the information wave field can guide the research and development of new information transmission technologies.In recent years,topological phase transition and boundary state transmission based on acoustic systems have attracted people’s research interest.Compared with traditional waveguides,topological boundary states can achieve unidirectional protective transmission of waves,immune defects,and other characteristics,and have higher pseudo-spin degrees of freedom.So it has more advantages in regulating wave transmission.Acoustic metamaterials have high design freedom and many characteristics that natural materials do not have,making them an ideal platform for acoustic topology implementation and testing.The topological boundary state has unique protective effect on the backscattering caused by the disorder.It is an ideal carrier of classical information and has important research significance in the fields of wireless communication,passive sensing,and information processing.Based on this,this paper studies the topological boundary states of phononic crystals in two-dimensional/three-dimensional systems and explores how to construct and realize phononic crystals with topological properties,to realize the flexible control of acoustic/elastic waves.The main tasks of this paper are as follows:1.Aiming at the problem that the existing work mainly focuses on the realization of topological states in a single form,a method for designing multi-form tunable acoustic topological devices by using a single structure is proposed.In the field of acoustic waves and elastic waves,topological structural units with the mixed component structure are designed respectively.Through two different rotation forms,the symmetry of the system is broken respectively,and the structure with acoustic pseudospin and topological boundary state is obtained.Finally,by constructing different phononic crystals and waveguides with complex transmission paths,the numerical simulation verifies that the designed structure has the characteristics of immune defects,high robustness,and controllable structure.The transmission characteristics of the elastic topological boundary state are further studied by vibration test.2.Aiming at the limitations of the microstructure design of pentamode metamaterials,the idea of using topology theory to construct acoustic/elastic wave control devices of pentamode metamaterials is proposed.Firstly,a pentamode metamaterial structural element with finite thickness is designed.The existence of topological properties is verified by calculating the Berry curvature.Secondly,the topological boundary state can be obtained by arranging the pentamode metamaterial topology,which can effectively protect the propagation of elastic waves.In addition,by measuring the vibration response of the sample,its topological properties in controlling elastic wave transmission were verified,which provides a new way to control acoustic/elastic waves using pentamode metamaterials.3.Aiming at the problem of multi-band topological valley transport,a method of realizing multifunctional acoustic devices with a single structure is proposed.Firstly,a clover-shaped structural unit with₃symmetry is designed.Multiple linear Dirac degenerate points can be obtained at K at the same time,which can realize multi-channel acoustic communication.Then,phononic crystals with different transmission paths are constructed,and their multi-band acoustic topology transmission characteristics are verified by numerical simulation.Finally,an acoustic beam splitter that can achieve different path outputs is designed.4.Aiming at the problem of ultra-wideband topological valley transmission,a design method of phononic crystal elastic plate structure is proposed.The elastic topological insulator is constructed by periodically arranging the scatterer structure on the bottom plate with a certain thickness.Then the edge states are used to realize the linear boundary,the right-angle turning boundary,and the valley topological transport with defects and disordered boundaries.Finally,it is found through experiments that the modulation of the edge state of the designed elastic phononic crystal plate can achieve more degrees of freedom and higher backscattering suppression ability,which provides a new idea for the engineering application of ultra-wideband acoustic antennas,acoustic logic control,and other devices.