MUTE-SIM: multiphoton up-conversion time-encoded structured illumination microscopy

Multiphoton microscopy (MPM) plays important role in biological imaging for its low scattering nature, yet it typically requires high illumination intensity. Although time-stretch of the ultrashort pulse can achieve ultrahigh speed scanning and deep penetration, the near-infrared illumination yields a compromised resolution because of its long wavelength. Here, by combining structured illumination with up-conversion materials, a multiphoton up-conversion time-encoded structured illumination microscopy (MUTE-SIM) with the scanning rate of 50 MHz is developed, which overcomes the limitation on the resolution. The resolution limit of near-infrared light is surpassed by a factor of 223.3% with low illumination intensity. This imaging strategy provides an ultrafast, low intensity, super-resolution MPM approach imaging, which has great potential in deep-tissue with high spatial resolution. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.