Topological resonance behaviors of surface acoustic waves under a surface liquid-layer loading and sensing applications

Abstract

In this work, topological resonance behaviors of surface acoustic waves (SAW) under a surface liquid-layer loading are investigated. By revealing influences of the liquid-layer loading on wave velocity of SAW and topological indices (Berry curvature and Chern number) of topological interface-modes, a topological resonance peak with a high Q-factor is obtained based on couplings of a topological interface-mode waveguide and a resonant cavity under a surface liquid-layer loading. The results show that the degree of spatial-inversion-symmetry breaking resulting from structure parameters has an obvious influences on the topological resonance Q-factor, while the influences of the thickness of the liquid-layer loading on that is weak. It is worth noting that the topological resonance frequency is significantly sensitive to the liquid parameters. Based on that, a novel topological-resonance SAW liquid-phase sensor is proposed. Furthermore, sensing performances of this kind of sensor are simulated, which are used to sensing the concentration of hemoglobin, albumin, NaCl and NaI in aqueous solutions, and high sensitivities and Q-factors are obtained. The results presented in this paper can provide an important basis for the realization of highly sensitive and stable SAW micro-liquid-sample biomedical sensors in the future.