Ultrasonic measurement is an important technique that is used in various fields of science and technology, including physical property evaluation, imaging and sensing. I use a measurement technique that uses light to excite and detect ultrasonic waves in the frequency range of GHz to THz, and I use this to evaluate the mechanical and acoustic properties of microstructures and thin films with sizes in the nano to micro range, as well as for non-destructive testing.

Conventional ultrasound had a wavelength of several micrometres or more, so it was impossible to measure at the nanoscale.
However, by using femtosecond pulse lasers to manipulate ultrasound with a wavelength of the order of 10 nm, I have achieved the evaluation of the mechanical properties of nano-materials and non-destructive testing in the nano-region.

• Development of unique measurement technology that makes full use of light and sound (lasers and ultrasound)
• Excitation and detection of vibration phenomena in nano-materials and GHz bands
• Accurate measurement of sound velocity and elastic constants under high magnetic fields of 10 to 600 K and up to 5 T
• Measurement of magnetic damping constants and saturation magnetisation from magnetisation oscillations in the time domain
• Main targets include nano-thin films of metals, piezoelectric materials, and magnetic materials, as well as superhard materials such as diamond and tungsten carbide
• Contributing to the development of materials and the elucidation of the characteristics of filters for wireless communication in smartphones
• Applications include the development of highly sensitive biosensors using ultrasound, which has a shorter wavelength than light, and monitoring the breaking process of nanowires

This measurement method enables the inspection of defects in semiconductors on the order of nm, and the evaluation of the characteristics of acoustic filters, which are essential for 5G communication devices.

• 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.

• Conventional X-ray imaging methods that rely on X-ray attenuation cannot generate clear contrast in the observation of low-density materials such as polymers consisting of low-Z elements. However, the sensitivity to the materials can be improved drastically by X-ray phase imaging that detects X-ray refraction caused by the materials. X-ray Talbot or Talbot-Lau interferometry consisting of X-ray transmission gratings is now constructed in laboratories for X-ray phase imaging. X-ray phase tomography is also realized, enabling high-sensitive three-dimensional observation.
• X-ray phase imaging can be utilized for X-ray non-destructive testing of industrial products and baggage that cannot be checked conventionally.

We aim at appending a phase-contrast mode to micro-CT apparatuses and developing screening apparatuses in production lines.