Acoustic Annular Slotted Resonators for Trapping and Sensing Sub-Wavelength Particles

Acoustic wave resonators have long been recognized as versatile, biocompatible tools for particle manipulation. However, their application in sensing the quantity and properties of particles remains a relatively underexplored research area. Herein, we propose an acoustic annular slotted resonator (AASR) system capable of simultaneously trapping and sensing subwavelength particles. The dual-function mechanism of this system originates from intense interactions between highly localized resonant acoustic fields and subwavelength particles within the subwavelength annular slot. Specifically, these interactions significantly enhance the acoustic radiation force, enabling efficient trapping of subwavelength particles at multiple stable positions. This trapping effect further amplifies the acoustic wave-particle interaction, ultimately boosting the system’s sensing performance. Numerical results demonstrate that the resonance frequency of the AASR system exhibits a strong dependence on both the quantity and type of subwavelength particles. Owing to its high sensitivity, compact size, and small amount of particle sample, the AASR system holds substantial potential for broad applications, including biochemical detection and environmental monitoring.