Snapshot photoacoustic topography through an ergodic relay for high-throughput imaging of optical absorption

A low-cost high-throughput photoacoustic imaging based on an ergodic relay coupled with a single-element ultrasonic transducer that can capture a wide-field image with only a single laser shot is demonstrated. Current embodiments of photoacoustic imaging require either serial detection with a single-element ultrasonic transducer or parallel detection with an ultrasonic array, necessitating a trade-off between cost and throughput. Here, we present photoacoustic topography through an ergodic relay (PATER) for low-cost high-throughput snapshot wide-field imaging. Encoding spatial information with randomized temporal signatures through ergodicity, PATER requires only a single-element ultrasonic transducer to capture a wide-field image with a single laser shot. We applied PATER to demonstrate both functional imaging of haemodynamic responses and high-speed imaging of blood pulse wave propagation in mice in vivo. Leveraging the high frame rate of 2 kHz, PATER tracked and localized moving melanoma tumour cells in the mouse brain in vivo, which enabled flow velocity quantification and super-resolution imaging. Among the potential biomedical applications of PATER, wearable devices to monitor human vital signs in particular is envisaged.