Transparent ultrasonic transducers based on relaxor ferroelectric crystals for advanced photoacoustic imaging
Chaorui Qiu, Zhiqiang Zhang, Zhiqiang Xu, Liao Qiao, 李宁 Li Ning, Shujun Zhang, Min Su, Weichang Wu, Kexin Song, Zhuo Xu, Long‐Qing Chen, Hairong Zheng, Chengbo Liu, Weibao Qiu, Fei Li
Abstract
Photoacoustic imaging is a promising non-invasive functional imaging modality for fundamental research and clinical diagnosis. However, achieving capillary-level resolution, wide field-of-view, and high frame rates remains challenging. To address this, we propose a transparent ultrasonic transducer design using our developed transparent Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 crystals. Our fabrication technique incorporates quartz-glass-and-epoxy matching layers with low-resistance indium-tin-oxide electrodes through a brass-ring based structure, enabling a high frequency (28.5 MHz), wide bandwidth (78%), and enhanced pulse-echo sensitivity (2.5 V under 2-μJ pulse excitation). Our Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3-based transparent ultrasonic transducer demonstrates a four-fold enhancement in photoacoustic detection sensitivity when compared to the LiNbO3-based counterpart, leading to a 13 dB improvement of signal-to-noise ratio in microvascular photoacoustic imaging. This enables dynamic monitoring of mouse cerebral cortex microvasculature during seizures at 0.8 Hz frame rates over a 1.5 × 1.5 mm2 field-of-view. Our work paves the way for high-performance and compact photoacoustic imaging systems using advanced piezoelectric materials. The authors develop a transparent ultrasonic transducer using Pb(In1/2Nb1/2)O3- Pb(Mg1/3Nb2/3)O3-PbTiO3 crystals, achieving enhanced sensitivity and bandwidth for photoacoustic microscopic imaging. This advancement enables dynamic microvascular monitoring, enhancing applications in brain research.