Fig. 5: Acoustic SAM-induced robustness on wave transport and SAM-related wave routing. | Nature Communications

Fig. 5: Acoustic SAM-induced robustness on wave transport and SAM-related wave routing.

From: Realization of acoustic spin transport in metasurface waveguides

Fig. 5

a The robustness can be reflected by the transmittance ratios of waveguides with/without metasurfaces to the unperturbed straight ones. The pressure fields are plotted in the normalized color bar. b The experimental settings. The source excites the waveguide modes and the pressure fields are measured by the detectors. The transmittance ratios are obtained by calculating the ratio between the U-shape waveguide and straight waveguide with the same length. c The experimental results show that the nonzero SAM of acoustic modes and the associated tight spin-momentum coupling will enhance the backscattering suppression. d The acoustic wave will selectively propagate along one side due to the SAM match when facing multiple channels. Reversing the incident acoustic wave spin will change outgoing waves to select the other channel with opposite spin. This acoustic spin-selective directionality is reminiscent of the spin-Hall-like effects for electrons and optics. e The experimental results to demonstrate the selective transport based on the matched SAM. The pressure field strengths at the port A and B are recorded. And the ratio between the port A and B will reflect this SAM-based selectivity. f The experimental results (blue line) show the strong selective phenomena. The red line means that the wave transport is divided equally in the normal T-waveguide without metasurfaces, namely A = B.

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