An Optically Transparent Focused P(VDF-TrFE) Transducer for Photoacoustic Microscopy (PAM)

This article reports a new optically transparent focused poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] transducer for photoacoustic microscopy (PAM), which is fabricated by a new process based on precutting and direct lamination. Compared with the previous fabrication process, it is simpler and makes it possible to achieve a high numerical aperture (NA) without stretching the (brittle) piezoelectric film. For demonstration, a prototype transducer has been fabricated with a 10- $\mu \text{m}$ -thick 70/30 P(VDF-TrFE) film laminated onto a plano-concave glass lens with an acoustic NA of 0.64. Experimental characterizations show that the transducer has an optical transmittance of 88.6% (@ 532 nm) and an acoustic center frequency and −3-dB bandwidth (BW) of 24 and 29 MHz, respectively. Using the new optically transparent focused P(VDF-TrFE) transducer, a PAM setup has been built to carry imaging experiments on different targets. Based on the experimental results, it can be concluded that the optically transparent focused P(VDF-TrFE) transducer could be useful for the development of new PAM systems for different imaging applications.