Nanophotonics for live cell observation with high resolution

We present superresolving optical imaging system and demonstrate the observation of biological specimens without any stained process. The electron-beam excited assisted (EXA) optical microscope has a few tens nanometer spatial resolution laterally and is possible to observe dynamic behaviors of specimens in various surroundings such as air or liquids. In the EXA-microscope, a nano-light source in a few nanometers size is excited by focused electron beam in an emission layer. An electron beam can be focused to a spot size as small as 1 nanometer in diameter. The EXA-microscope enables to observe optical constants such as absorption, refractive index, polarization properties, and its dynamic behaviors in nanometer scale. We also have developed a direct electron-beam excitation assisted optical microscope with a resolution of a few tens of nanometers and it can be applied for observation of dynamic movements of nanoparticles in liquid. In the microscope, fluorescent materials are directly excited with a focused electron beam. In this paper we present the evaluation result of resolution and observation results of living HeLa cells with high resolution. We have successfully observed fine structures of the cells without any stain process. This is first demonstration of observation of intercellular granules in HeLa cells.