Time-resolved imaging of ultrasound waveform with synchronized laser illumination

We present a synchronous time delay technique to precisely control the illuminating laser pulses and the ultrasonic wave generation to visualize the ultrasound waveform through the Schlieren imaging method. The proposed time-resolved imaging technique offers the two-dimensional mapping of ultrasound waveform in a temporally evolved manner. The critical physical parameters, such as speed and spatial pulse length of ultrasonic waves, are visualized and calculated from image analysis. Our results suggest a protocol in characterizing ultrasound waveform, and it has the potential to reconstruct the acoustic field by accumulating the time-lapse waveforms.