Multiphoton upconversion in rare earth doped nanocrystals for sub-diffractive microscopy

Abstract

A major bottleneck in microscopic imaging is the limited lateral resolution due to the diffraction of light. To overcome this limit, here we demonstrate the upconversion process in rare earth doped nanoparticles (RE:NPs), which may serve as an original fluorescence-source mechanism. RE:NPs have been reported to serve as efficient bio-labels for cellular and small animal imaging. In this work, we demonstrate that non-linearity of upconversion allows achieving high lateral resolution in the images using multiphoton microscopy, demonstrating significant improvement in lateral resolution, using low pumping laser power. This new technique may serve as another approach for high-resolution optical imaging. © 2013 American Institute of Physics.