Fig. 1. (a) Schematic of an airborne honeycomb-lattice sonic crystal (SC) composed of gear-like rods; (b) dispersion relation of SC-I.(a)基于齿轮形散射体组成的蜂窝晶格声子晶体原胞; (b)声子晶体I(r = 0.3671b, R = 0.455b, θ = 20°和α = 15.67°)的色散关系

Fig. 2. Dispersion relations of (a) SC-II and (b) SC-III; (c) distributions of pressure field for eigenmodes at Brillouin zone center of SC-II and SC-III.声子晶体(a) II (r = 0.375b, R = 0.477b, θ = 26°和α = 22°)与(b) III (r = 0.35b, R = 0.44b, θ = 20°和α = 0°)对应的色散关系; (c)声子晶体II与III在布里渊区中心的本征模式声压场分布

Fig. 3. (a) Schematic of a supercell composed of SC-II and SC-III. Red dashed line represents the domain wall between two SCs; (b) dispersion relation of the supercell; (c) simulated pressure eigenfunctions (S and A modes) of the supercell at point N (k_|| = 0.05) in Fig. (b); (d) simulated acoustic energy flow for pseudospin-dependent edge modes at points M and N (k_|| = ± 0.05) in Fig. (b). (a)声子晶体II与III组成的超原胞结构, 红虚线表示两种声子晶体之间的界面; (b)超原胞对应的色散关系; (c)超原胞的对称模S与反对称模A声压本征场分布(图(b)中N点, k_|| = 0.05); (d)超原胞的边缘模式声能流场分布(图(b)中M点与N点, k_|| = ± 0.05)

Fig. 4. (a) Photograph of a topological waveguide composed of SC-II and SC-III. Red dashed line represents the domain wall of two SCs. Simulated distributions of acoustic intensity field at 9.1 kHz (within bulk band gap) through topological waveguides with three different configurations, corresponding to (b) without defects, and with (c) a disorder and (d) a bend. Green star and arrows represent source positions and propagation directions.(a)基于声子晶体II与III的声拓扑波导样品, 红虚线表示两种声子晶体的界面. 数值模拟频率为9.1 kHz (体带隙内)的声波通过三种类型的拓扑波导产生的声能量密度场分布, 三种拓扑波导分别对应(b)无缺陷, 含内置(c)无序与(d)弯曲缺陷. 绿色星与箭头分别表示声源位置和声传播方向

Fig. 5. (a) Experimental setup; (b) measured transmission spectra for topological waveguides without and with two types of defects; (c) dispersion relation of the supercell at 303 K.(a)实验装置示意图; (b)实验测量无缺陷与内置无序与弯曲缺陷的声拓扑波导对应的声透射谱; (c)超原胞在室温为303 K对应的色散关系

Fig. 6. Dispersion relations of (a) SC-I, (b) SC-II and (c) SC-III in high-frequency region (around 24.44 kHz); (d) distributions of pressure field for eigenmodes at Brillouin zone center of SC-II and SC-III in high-frequency region.声子晶体(a) I, (b) II和(c) III在高频区间(24.44 kHz左右)的色散关系; (d)高频区间对应的声子晶体II与III在布里渊区中心的本征声压场分布

Fig. 7. Dispersion relations of a supercell in high-frequency region (around 24.44 kHz).超原胞在高频区间(24.44 kHz左右)的色散关系