Ultrawideband sub-pascal sensitivity piezopolymer detectors

Piezoelectric detectors are integral part of modern ultrasound imaging systems. Their utility has also been extended beyond the established methodologies into the emerging realm of hybrid optoacoustic imaging. Conventional piezoceramic detectors, however, struggle to combine high detection sensitivity with ultrawide bandwidth, both considered critical for attaining optimal optoacoustic imaging performance. Our research, both theoretical and empirical, unveils that damped piezopolymer detectors fabricated from PVDF-TrFE are markedly capable of achieving a synergistic blend between broad bandwidth and superb sensitivity. Experimental evaluations reflected an average sensitivity of 15.5 µV/Pa within a 1-10 MHz band for a 120 µm thick detector and 6.4 µV/Pa within a 1-30 MHz band for a 20 µm thick detector, thus outperforming conventional piezoelectric analogues. The resultant noise equivalent pressure (NEPs) values were 0.3 Pa and 1.2 Pa for the 20 µm and 120 µm detectors, respectively. Our findings herald a significant stride towards enhancing the efficacy of ultrawideband ultrasound and optoacoustic imaging systems.