His majoring has been high-resolution and in-situ electron microscopy and diffraction of small particles and clusters. Dr. Tanaka is studying nano-structure science, thin film physics, catalysis science, and surface/interface physics by using aberration-corrected high-resolution electron microscopy including phase imaging, environmental electron microscopy and electron tomography. He is also interested in magnetic properties of transition metal clusters and micro-devices studied by using spin-polarized and vortex electron beams as well as EELS.