Two-Photon Imaging

High-Throughput Imaging

    Two-photon microscopy (TPM) is now instrumental in a wide range of in vivo biological imaging applications, but it is still challenging to meet the needs for fast monitoring of biological dynamics and large-scale examination of biological heterogeneity. Therefore, it is essential to develop high-throughput two-photon microscopes.  Diffraction-free beam, such as Bessel and Airy beam, has an axially elongated PSF, which can simultaneously read out the TPF signals within the extended axial range, thus making the 2D scan rate equivalent to the volumetric rate. This is useful for imaging sparsely labelled structures with minimal structural overlap in their 2D projections at a significantly scaled up speed.  Non-telecentric optical design illuminates the objective’s back-aperture with a de-collimated and divergent beam, which can effectively break the constraints of conventional two-photon microscopes on the size of the imaging field-of-view. This method offering a several-fold expanded three-dimensional imaging FOV and achieving a highly efficient information acquisition.

Endoscopic Imaging

    Two-photon endoscopy microscopy imaging system based on multimode fiber is under development.  Using a digital micro-mirror device (DMD) to modulate the transmission mode in the multimode fiber, a spatiotemporal compact focus will be generated at any specified point in space at the distal end of the multimode fiber.  This system is expected to be combined with two-photon autofluorescence imaging to achieve label-free in-vivo dual-mode (structural imaging and functional imaging) deep tissue imaging such as brain and digestive tract.