Abstract

Two-photon fluorescence microscopy can observe deep biological structures with high spatial resolution. However, when deeper observation is desired, the signal-to-noise ratio deteriorates due to signals from out-of-focus areas, making observation difficult. To solve this problem, we propose an imaging method by detecting photoacoustic waves instead of fluorescence generated by overlap modulation as proposed in two-photon fluorescence microscopy [1]. This method detects the photoacoustic signal caused by overlap modulation only near the focal spot, thus eliminating the signal from outside the focal spot, and enables high contrast and deep imaging. In this study, we conducted a basic investigation of two-photon absorption modulation to construct a two-photon photoacoustic microscope [2] with overlap modulation.

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