Ultrasound-modulation assisted multiphoton imaging

Two-photon microscopy provides sectioned excitation, but in practical settings, it often suffers from contrast limitations. Here, we report the observation of a strong acousto-optic modulation of two-photon excited fluorescence. Harnessing this effect yields enhanced image detail and contrast and improves optical sectioning in deep brain tissue in vivo. Ultrasound-modulation assisted multiphoton imaging (UMAMI) is compatible with standard multiphoton microscopes, without requiring changes to the optical path or image acquisition parameters.