Sensitive ultrawideband transparent PVDF-ITO ultrasound detector for optoacoustic microscopy

An ultrasound detection scheme based on a transparent polyvinylidene-fluoride indium-tin-oxide (PVDF-ITO) piezoelectric film is developed for ultrawideband sensitive detection of optoacoustic (OA) signals down to a noise equivalent pressure (NEP) of 8.4 Pa over an effective detection bandwidth extending beyond 30 MHz. The high signal-to-noise ratio and low noise performance are facilitated by employing a two-stage amplifier structure. The PVDF-ITO detector is directly mounted on a commercial high numerical aperture objective lens of a scanning optical resolution OA microscopy system to obtain submicron resolution images without signal averaging, as demonstrated both in phantoms and in vivo measurements in mice. The transparent detection scheme further allows for the OA imaging modality to be easily integrated with other imaging techniques for diverse multi-modal biomedical imaging investigations.