High-speed dual-layer scanning photoacoustic microscopy using focus tunable lens modulation at resonant frequency.

The range of imaging depth in optical resolution photoacoustic microscopy (PAM) is limited by the short depth of focus of high-numerical aperture objective lenses. In this paper, focus tunable lens modulation has been employed at the resonant frequency of focus tunable lenses in order to enhance both the range of imaging depth and the scanning speed. By electrically controlling the focal length in the axial direction of the sample, the range of imaging depth was extended approximately 1.22 times and the scanning speed was enhanced by approximately 7.40 times, in comparison to corresponding values of conventional PAM systems.