High resolution imaging with a polyimide-etalon all-optical ultrasound transducer

We previously reported the performance of an all-optical high-frequency ultrasound transducer consisting of a UVabsorbing polyimide film integrated into an etalon receiver. In this work, we demonstrate the imaging capabilities of a synthetic array of these elements in two different configurations: (1) fixed transmitter, scanning receiver and (2) fixed receiver, scanning transmitter. The first configuration involved a 2 mm transmitting element and a 33 μm receiver element scanned over a 2 × 2 mm aperture at 30 μm increments. The reconstruction of two 50 μm wires placed at 1.2 mm and 4.9 mm depth demonstrated an axial resolution of 41 μm and 42 μm, respectively, and a lateral resolution of 73 μm and 137 μm, respectively. The second configuration involved a fixed, 33 μm receiver and a 200 μm transmitting element scanned over a 2 × 0.2 mm aperture at 20 μm increments. Imaging of an 80 μm wire placed at 4.3 mm depth yielded an axial resolution of 37 μm and a lateral resolution of 145 μm.