半导体软激光有什么用专题二、先进激光材料、薄膜及元器件，新型功能光纤与器件

摘要：Lanthanide-doped photon upconversion nanoparticles (UCNPs) are capable of converting low-intensity near-infrared light to UV and visible emission through the synergistic effects of light excitation and mutual interactions between doped active ions. UCNPs have gained increasing attention for their wide applications in optical bioimaging, displays and related nanophotonics. However, there are still some ongoing challenges for further development. In this talk, some strategies of optically controlling the optical properties of UCNPs for extended applications will be introduced. The performance of imaging employing UCNPs, e.g., imaging depth, imaging speed, PL brightness and spatial resolution have been greatly improved for applications. For example, in 2015, we firstly realized optical emission depletion of common UCNPs and its potential for super-resolution optical microscopy. Recently our group has developed a novel, in-depth STED mechanism using optimized lanthanide upconversion nanoparticles. We experimentally demonstrated very efficient optical depletion for the UCNPs and successfully archived highly efficient, absolutely non-bleaching cytoskeleton STED imaging at subcellular scale. These findings have great potential in low power, photobleaching-free super-resolution microscopy.