Fabrication of high-frequency ultrasonic array transducers with outstanding performance based on laser techniques

The excellent performance of PMN–PT has received increasing attention and applications in high-frequency (>20 MHz) ultrasonic array transducers. However, due to its brittleness and low phase-transition temperature of PMN–PT, a decrease of piezoelectric properties in the fabrication of small-scale array elements is still an urgent problem and would substantially determine the performance of transducers. Here, in this study, ultrashort pulse laser technique is proposed to fabricate PMN–PT array transducers with outstanding performance. The effect of the laser parameters on domain structures has been studied systematically, and it was found that the ultrahigh piezoelectric properties of micro-sized elements still maintained after optimizing the laser parameters. A Fresnel array transducer with center frequency of 40.84 MHz and −6dB bandwidth as high as 122.28% was also designed and fabricated. This work demonstrates that it is feasible and promising to fabricate superior PMN–PT and other piezoelectric ultrasonic array transducers based on ultrashort pulse laser techniques.