Wideband linear detector arrays for optoacoustic imaging based on polyvinylidene difluoride films

We provide direct experimental comparison of the optoacoustic imaging performance of two different 64-element linear detector array (LDA) units based on polyvinylidene difluoride (PVDF) films. The first LDA unit was based on traditional flexible circuit (FC) technology and consisted of an FC glued to the nonmetalized signal surface of a 28-μm-thick PVDF film providing 300  /  80-μm axial resolution/lateral resolution (AR/LR) and 0.4-kPa noise equivalent pressure of its single element. The other LDA unit was manufactured using a technology of low-temperature photolithographic etching (PE) of a signal electrode onto a 25-μm-thick PVDF film providing 300  /  40-μm AR/LR and 1 kPa noise equivalent pressure. As compared with a previously reported LDA unit based on a 100-μm PVDF thick film, the main advantage of using the thinner PVDF films was 10-fold improvement in axial resolution, whereas the main drawback was 10-fold increased noise equivalent pressure. In terms of in vivo imaging performance, higher bandwidth of PE LDA probe was more important than the higher sensitivity of FC LDA unit.