Oral:Topologically protected acoustic energy enhancement via controllable valley-Hall edge states

The pursuit of robust energy enhancement has garnered significant attention across multiple fields of acoustic engineering. Here, we propose a feasible approach to realizing sound energy enhancement in an acoustic topological waveguide (ATW) with gradient gap width. By modifying the width of the topological bandgap, we can tune the capability of energy confinement within a desired region while benefiting from topological protections that render the system immune to certain types of defects. The ATW, stemmed from mimicking quantum valley Hall effect (QVHE), is constructed by employing two types of C<sub _msthash="556" _mstmutation="1" _msttexthash="4641">3-symmetric sonic crystals (SCs) with distinct valley Chern numbers, through topology optimization. Both numerical and experimental results demonstrate robust edge states and enhanced energy confinement, even in the presence of non-spin-mixing defects. This work shows a leap forward in designing acoustic functional devices and may inspire potential applications in areas such as acoustic imaging, energy harvesting, and communication systems.