Variable-thickness multilayered polyvinylidene fluoride transducer with improved sensitivity and bandwidth for photoacoustic imaging

The performance of photoacoustic imaging (PAI) is critically dependent on the sensitivity and bandwidth of the transducer. Here, we report the design and fabrication of a polyvinylidene fluoride ultrasonic transducer with variable-thickness layers that demonstrates significantly improved sensitivity and bandwidth. We show that the multilayered transducer provides more than 2-fold increase in sensitivity and more than 65% improvement in bandwidth compared with the conventional single-layer transducer. Photoacoustic imaging of mouse brain with the intact skull and scalp is conducted to demonstrate the power of the multilayered transducer for resolving brain structure in an in vivo setting.