• In our laboratory, miniature and highly-functional photonic devices based on new optical phenomena caused by the interaction of ultrafine microstructures with light have been studied. In addition, development of new production technology to overcome the problems that have been obvious from the practical application viewpoint of nanophotonic devices has been performed.
• • -Main research topics--
  MEMS tunable metamaterials for optical control.
• Structural color filters using subwavelength gratings for the applications of display and spectroscopic analyzers.
• Surface-smoothing technology using surface self-diffusion.
• Study of low loss silicon nanophotonic devices.

We aim to realize optical filters, optical resonators, and color filters, by using above technologies. Also, development of nano-photonic elements fabricated by a nanoimprint technology has been progressed.
We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• Our research aims at developing methods, including instrumentation, for characterizing surface (or interface) at the nano-meter level. Most of our research subjects are related to the surface forces measurement, which can directly monitor the interaction between two surfaces. We study phenomena occurring at the solid-liquid interface such as adsorption and structuring of liquids. We have developed the resonance shear measurement which is a sensitive method for evaluating properties of confined liquid for nano-rheology and tribology. Twin-path surface forces apparatus we developed enabled us to study wide variety of samples such as metals, ceramics and plastics.

These methods are applicable for characterizing lubricants, nano-materials, paints, sealants, and cosmetics. We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• Since we have developed the techniques (ion control plasma) to generate and control ions, electrons, reactive species (radicals) in the low temperature non-equilibrium plasmas which I can touch by hand, the composite materials using nanoparticles, nanocarbons, biological molecules are synthesized in the nano-electronics field, the minimally-invasive and highly-efficient drug/gene transfection systems are developed in the medical field, and bacteria and insects are killed by the plasma in place of pesticide in the agricultural field.

The ion-controlled plasmas are applied for the minimally-invasive gene transfection system, next-generation agricultural system, the electrode material of highly-efficient battery, and so on. We hope to conduct the collaborative research with a willing company for a practical application of the novel plasma nano-medical-agricultural applied technology in industry.

• Plasma sterilization has been developed as an alternative sterilization method due to its chemical activity, operation at low temperature and atmospheric pressure, low power consumption, low cost and safety. We have studied a mechanism of chemical species generation and transport in a plasma flow and, the sterilization efficacy and mechanism for several plasma sources at atmospheric pressure, such as a microwave plasma flow, a dielectric barrier discharge in a tube and a water vapor plasma flow. We already clarified that the damages of outer membrane and destructions of the cytoplasmic membrane of Escherichia coli by exposure to the microwave plasma flow. Fig. 1 shows the effect of plasma exposure on the E. coli. When the E. coli was exposed to the plasma, the height of the E. coli decreased and the potassium leakage of cytoplasmic material increased. For sterilization in a tube, we also clarified that an induced flow in the narrow tube by DBD transports chemical species and sterilize the whole inside surface of a tube as shown in Fig. 2. We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• Our research target is mainly focused on the topic of development of novel scintillator crystals, piezoelectric crystals, growth technology, characterization and its device application.
• We design and synthesize new materials from a view point of Crystal Chemistry, and investigate their structure and physical properties. We also study on photo-detector, as suitable photo-detector fully contribute to get maximum signal from scintillator. This activity is very important to realize practical application of our developed materials. Recently, piezoelectric material and high melting temperature alloy project is also started.

For the purpose of "real" contribution to human culture, we are always carrying out our research activity considering the industrial application. This point is unique feature of our attitude toward science.

• Nanoporous metals have drawn considerable attention due to their highly functional properties. They are generally produced by selective dissolution of elements from a multicomponent alloy (known as the dealloying method). As this method is based on differences in the electrode potential of each element present in the alloy, and this potential is high for noble metals, porous structure can be obtained only for noble metals. Recently we have found a new, simple and easy dealloying method without using aqueous solution, which enable us to develop an open nanoporous non-oxidized metallic material even with base metals (such as Ti, Ni, Cr, Fe, Mo, etc), metalloids and their alloys.

This technique is very powerful for developing new functional electrodes, catalysts, filters as well for removing toxic metallic element from the surface of biomaterials containing the toxic element.