Research On New Topological Materials Based On Acoustic Artificial Microstructure

One of the most important directions in condensed matter physics is the discovery and study of new phases of matter,and the introduction of the concept of topology into physics,which played a decisive role in the discovery of topological phases,has received much attention in condensed matter physics.The study of topological physics has also been extended to acoustic systems and has gradually developed into one of the most popular research areas.In this paper,by introducing the concept of topology into the acoustic waveguide system and localized acoustic structure,the acoustic topological π-mode,acoustic non-adiabatic topological pumping and localized acoustic skyrmions are realized in the acoustic research context,and the topology is verified in different acoustic structures through simulations and experiments,further deepen the understanding of arbitrary manipulation of acoustic waves.The specific research of this paper is as follows:1.Realizing the topological π-mode in the discrete waveguide array by adjusting the coupling strength between the waveguides and adjusting the bending period of the waveguides,and the acoustic waves are transmitted periodically along the edges of the waveguides,and we compare them with those under the banal waveguide structure to verify the topological properties of the waveguide array,which provides a good platform for the subsequent research.2.In the discrete waveguide model designed by the above concept,a topologically protected pumping structure is proposed to apply topological pumping to acoustics,where the current studies of pumping in acoustics are under adiabatic conditions,and this structure is very unstable.Here,we design a structurally stable and non-adiabatic topological pumping structure to demonstrate the dynamic topological pumping of acoustic pulse signals propagating in physical time(t)and propagation coordinates(z).The topologically pumped transmission of continuous and pulsed acoustic waves demonstrates the practicality of the designed waveguide array for dynamic signal transmission and wave manipulation.3.Designing a spiral structure at subwavelength scales to realize the skyrmions mode in the acoustic system in real space,the resonant response of the superstructure is analyzed and the spatial distribution of its velocity field is observed,and the topologically protected skyrmions mode supported by the subwavelength structure is verified to be robust to structural defects by simulation,and the designed real-space acoustic skyrmions topology may open a new way to design ultra-compact acoustic devices to manipulate acoustic waves.