Fig. 3: From laser point scanning to fast, wide and deep volumetric imaging in complex samples with TPE.
From: More than double the fun with two-photon excitation microscopy
a Scheme for conventional TPE laser scanning microscopy which requires scanning of the excitation/emission (orange ellipse) through x,y, and z dimension and collection of every single point onto a point detector. b Scheme for TPE light-sheet excitation and detection using a camera. Scanning is only required in z-dimension. c TPE scheme for digitally scanned light-sheet. The virtual sheet is created by scanning an extended TPE beam in y-dimension faster than the camera frame rate (orange double-arrow). Volumetric imaging is achieved by scanning in z-dimension. The camera detection integrates multiple scans of the beam in y-dimension into a single frame. d Scheme for scanless volumetric detection using light-field technology. The microlens array in front of the camera allows capturing z information from an excited volume at the expense of lateral resolution. A volume of illumination is generated by quickly scanning the virtual sheet along the z axis to excite and capture a volume in a single snapshot. “Human brain outline in lateral view” by an unknown author from Wikimedia Commons licensed under CC0 1.0. e, f Combination of light-field detection with two (e) or one (f) objective digitally scanned light-sheet excitation while selectively exciting a volume of interest. g TPE laser scanning microscopy in combination with an implanted GRIN lens for deep tissue imaging in live animals. WD Working distance, GRIN Gradient of refractive index.
