Abstract
In vivo two-photon microscopy has revealed vital information about neural activity for brain functions, despite its limitations when imaging events at depths greater than several hundred micrometers from the brain surface. To break the limit of this penetration depth, we introduced a novel photon detector that successfully visualizes not only the cortex layer V pyramidal neurons spreading to all cortex layers at a superior S/N ratio but also visualizes the hippocampal CA1 neurons in young adult mice. In addition, we developed liquid crystal devices to convert linearly polarized beams (LP) to vector beams. A liquid device generated a vector beam called a higher-order radially polarized (HRP) beam for identifying individual fluorescent beads whose diameters were 170 nm, which is smaller than the classical PSF width. HRP beams also visualized the fi ner structures of microtubules in fi xed cells. Here, we discuss these improvements and future applications based on our recent data.
