Twin Trap Acoustic Transducer with PDMS Fresnel Lens for Particle Trapping

Acoustic manipulation has a wide range of applications in medicine and bioscience due to its contactless and high penetration capabilities. The twin trap has been shown to be particularly effective acoustic trapping mode. However, most current studies utilize a phase-controlled array to generate the twin trap acoustic field, which is both complicated and bulky. In this paper, we present a compact and easy-to-fabricate Fresnel Lens Twin Trapping Acoustic Transducer for trapping particles. This transducer is fabricated using MEMS processes, enabling high precision and batch production. The transducer consists of a bulk Piezoelectric Transducer (PZT) and a Polydimethylsiloxane (PDMS) film with air cavities. The pattern of the air cavity is designed as an acoustic Fresnel lens. Acoustic waves passing through the lens generate two horizontal acoustic focal points that trap particles in the middle. Compared to other methods, this transducer is highly compact and portable.