Fig. 2.

(a) Schematic of the PMN-PT focused US transducer. (b) Front view of the implemented US transducer, showing the optical fiber located at the center. Scale bar, 500 µm. (c) Diagram showing the dimensions of the plastic acoustic lens, membrane position, and targeted working distance. (d) Simulated two-dimensional (2D) transmission acoustic field of the focused US transducer. The –6dB beam diameter at the 4-mm focal distance is ~80 µm. The vertical and horizontal axes represent transverse and radial (axial) distances from the US transducer.