Functional Plasmonic Materials
- high sensitivity and compact bio/environment sensors -
Biosensors detect low buncdance analytes that are typically biomolecules, such as proteins, nucleic acids etc, in the blood. Such devices are used for diagnosis as well as for drug development. For "plasmonic" biosensing, we utilize oscillation of free electrons in metallic materials, so called "plasmon". Since the plasmonic resonance is extremely sensitive to the surface permittivity change and the plasmonic resonance can be confined in nanoscale, super sensitive portable sensor devices are expected. Such technology would realize cancer diagnosis at home as well as high through-put diagnosis in the hospital, sensitive pollutanct detection in the field, etc. In our group, we cleverly combine self-assembly and lithographic technique to control the confinement of free electrons to tune the plasmonic resonance for new type of plasmonic sensing devices. We are also good at controlling the combosition, crystallinity, electron energy and mesoscopic structure of such materials.
We have various national and international collaborations such as ETH Zurich, Chalmers Univ. Tech., Weizmann Inst., Kyushu Univ., etc.
Visualization of Surface Plasmons
- Cathodoluminescence Scanning Transmission Electron Microscopy -
Confined light field in nanoplasmonic structures is not accessible by ordinary techniques based on light. We observe surface plasmons excited by accelerated electron beam. This technique (cathodoluminescence) enables visualization of the light field with 1 nm spatial resolution in combination with aberration corrected scanning transmission electron microscopy (STEM). Spectro-scopic mapping of the emitted light gives us real space light field distribution at different wavelengths.
Development of Transmission Electron Microscopy Techniques
- Create "Eyes" for Material Research -
Transmision electron microscopy (TEM) with atomic resolution is an indispensable tool to develop new materials. Since its appearance in the early 20th century, it is still evolving. We are developing new TEM-based techniques and applications, as well as new STEM-CL methods. Such new "eyes" discover new materials and create new science.
We have collaborations related to this research with National Inst. Physiological Sci. as well as industries, such as Terabase Inc., and JEOL Ltd.