Transparent ultrasonic transducers based on relaxor ferroelectric crystals for advanced photoacoustic imaging

• Published in: Nature communications 2024-12, Vol.15 (1), p.10580-14
• Main Authors: Qiu, Chaorui, Zhang, Zhiqiang, Xu, Zhiqiang, Qiao, Liao, Ning, Li, Zhang, Shujun, Su, Min, Wu, Weichang, Song, Kexin, Xu, Zhuo, Chen, Long-Qing, Zheng, Hairong, Liu, Chengbo, Qiu, Weibao, Li, Fei
• Format: Article
• Language: English
• Subjects: 631/1647/245; 639/301/1005/1009; Cerebral cortex; Crystals; Fabrication; Ferroelectric crystals; Ferroelectricity; Field of view; Frame design; Humanities and Social Sciences; Indium tin oxides; Lead; Lead titanates; Lithium niobates; Matching layers (electronics); Medical imaging; Microvasculature; multidisciplinary; Neuroimaging; Noise levels; Noise monitoring; Piezoelectricity; Science; Science (multidisciplinary); Seizures; Signal to noise ratio; Silica glass; Transducers; Ultrasonic transducers
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-55032-0

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(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 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(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 -based transparent ultrasonic transducer demonstrates a four-fold enhancement in photoacoustic detection sensitivity when compared to the LiNbO 3 -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 mm 2 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(In 1/2 Nb 1/2 )O 3 - Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 crystals, achieving enhanced sensitivity and bandwidth for photoacoustic microscopic imaging. This advancement enables dynamic microvascular monitoring, enhancing applications in brain research.