The first topic is demonstration of high spatial resolution in 3D of the new microscope SAX (saturated excitation microscopy) invented here at the photonics center (see figure # 1). A SAX microscope is a high resolution microscope which picks up for imaging only the fluorescent dye molecules of a sample whoes excited states are satulated. As satulation is optical nonlinear effect (proportional to the square or higher power of incident radiation intensity), distribution of satulated molecules is confined in much narrower regions compared with the intensity distribution of light. In the demonstration, actin filaments of living cells cultured in three dimensions were successfully observed at high-spatial-resolution in three-dimensional directions. As a living body is originally three-dimensional, there is much scattering light compared with a thin two-dimensional sample and thus it is difficult to carry out high resolving observation optically. The success of SAX high resolution observation in 3D indicates that it will play an active part in the biomedical field.
Secondary, the nonlinear effect of the plasmon of a gold nanoparticle (80 nm) is investigated for a single nanoparticle not particles ensemble and the point spread function could be narrowed to 1/5 of a wavelength (structure of narrow edge to 1/13) by a nonlinear effect showing that a high resolution image can be obtained (see figure # 2).
Thirdly, chemical states of a small bio-molecule in living cells are successfully imaged by Raman microscope; protonated and deprotonated FCCP molecule are identified and imaged (see figure # 3). FCCP is a small molecule which controls activity of a cell: conveys proton through a bio-membrane. This is the first time to have identified such different states of small bio molecule in vitro.
For more details, please take a look at Research.