报告内容摘要

The development of super resolution techniques, such as stimulated emission depletion (STED) microscopy and single-molecule localization microscopy, has successfully demonstrated high-resolution fluorescence imaging far beyond the diffraction limit and has been chosen for Nobel prize in chemistry in 2014. These techniques effectively utilize interactions between light and molecules to manipulate fluorescence emission properties to break the diffraction limit. Using the optical nonlinearity is a simple approach to utilize light and fluorescent probe interactions for the resolution improvement in confocal microscopy.

We have proposed a use of saturation effect in fluorescence excitation to induce the nonlinear relationship between excitation and emission intensities in order to break the resolution limit in confocal microscopy. The technique does not require additional optics from a confocal microscopy setup, and changing of excitation intensity during measurement is only a requirement. We also found that saturated emission can also be observed in light scattering at metallic nanoparticles. The saturation of plasmonic scattering induces highly nonlinear responses in light scattering that also allow us to break the limit.

报告人简介

Katsumasa Fujita is an associate professor of Applied Physics at Osaka University. He received his BSc, MSc, and PhD from Departmemt of Applied Physics, Osaka University in 1995, 1997, and 2000, respectively, with his achievement in development of laser scanning microscopy for tissue imaging. After finishing the PhD study, he joined Kyoto Prefectural University of Medicine as a posdoc supported by Japan Society for the Promotion of Science (JSPS) and studied optical cell imaging and manipulation and their applications in biomedical researches. Two years later, he joined Osaka University as an assistant professor in 2002, and he was promoted to an Associate Professor of Applied Physics in 2007. His current research interest is development of new techniques in super-resolution microscopy and Raman microscopy.