INTRODUCTION OF LABORATORY

We can explore the origin of the electronic structure of materials responsible for their electronic, magnetic, and optical properties using extremely intense X-rays with a desired energy and high energy resolution that can be obtained using synchrotron radiation. Our home ground is SPring-8, one of the highest brilliant synchrotron facilities in the world; it is where we have developed noble and original spectroscopies for material science in 'soft' X-ray region in-between vacuum ultraviolet rays and X-rays. In particular, we are leading the world in soft X-ray emission spectroscopy, a kind of light scattering, promising for electronic structure analyses of liquids and operando spectroscopy of a variety of catalysts. Our studies include: *observation of elementary excitations (crystal field excitation, spinon, magnon, charge density wave, orbiton etc.) in strongly correlated materials like Mott insulators and noble high temperature superconductors *electronic structure analysis of aqueous solutions to study microheterogeneity and interaction at solid-liquid interfaces *development of in situ soft X-ray spectroscopy for surface reaction of fuel cell catalysts, electrochemical  reaction, and photocatalytic reaction *electronic structure analysis of reaction center in metalloproteins *basic study on ultrahigh energy resolution optics for soft X-ray emission and time-resolved spectroscopy

YOSHIHISA HARADA LAB. research

 

高分子電解質ブラシの中に浸透した水( Confined water)。

YOSHIHISA HARADA LAB. research

 

軟X線非弾性散乱で捉えた常温の水(緑)、氷(青)と高分子電解質ポリマーブラシに浸透した水(赤)の比較。

Message

FROM INTERESTS IN LIGHT ITSELF TO ITS INTERACTION WITH MATTER; I BELIEVE RESEARCH QUALITY DEPENDS ON HOW IT CAN BROADEN ONE'S INTERESTS.

We recognize a material's color by detecting a visible light that we call green, yellow or red in the case of a leaf, which depends on the absorption or transmission property of the light reflecting complex interaction between the light and the material. When a material is illuminated by a light called "soft X-ray", we see another "color" that provides a lot of information about the origin of the electronic and magnetic property and local bond coordination, local symmetry and so on. We are currently developing soft X-ray emission spectroscopy, a tool to detect such soft X-ray "color" with an intense and well-organized (color, size, polarization, position, time-structure and so on) soft X-ray light source called synchrotron radiation. With only a slight advance in the sample handling, we can extend the target of this noble spectroscopy and obtain new information that cannot be made available by other methods. For example, pure liquid water, which is entirely transparent in the visible light region, looks inhomogeneous in terms of the energy distribution of valence electrons responsible for hydrogen bond formation when observed by soft X-rays. Four years ago, we reported the inhomogeneity of liquid water, which became a subject of discussion worldwide and is still much debated in water-related international conferences and on journal papers. Soft X-ray emission spectroscopy is such a powerful technique that provides us a chance to explore new fields.

PROFILE

Professor Yoshihisa Harada

Professor Yoshihisa Harada

He graduated from the University of Tokyo and got a Ph.D. degree (2000) under the supervision of Professor Shik Shin. He was a fellow of Japan Society for the Promotion of Science (JSPS) and then moved to RIKEN/SPring-8 as a postdoctoral researcher (2000-2007). He was appointed as project lecturer (2007-2009) and project associate professor (2009-2011) at the University of Tokyo. He became Associate Professor at ISSP, the University of Tokyo in 2011 and was promoted to Professor in 2018.

STUDENT VOICE

Ayako Kameda

Ayako Kameda

Prof. Harada is at the forefront of soft x-ray research and is actively pioneering new research subjects. He is also keen to teach students, giving polite and thoughtful comments, and is always willing to help us with various consultations. Our laboratory's characteristics are that it is located in a large synchrotron radiation facility, SPring-8, where we can conduct research surrounded by a lot of instrumentations and many researchers from various fields. Many of our members are overseas, and we enjoy our daily activities in this luxurious environment and global atmosphere (and nature!).


Visiting laboratory

  • +81-791-58-0802-3966(harima)
  • +81-4-7136-3401(kashiwa)
  • Yoshihisa Harada Lab.,
  • Department Of Advanced Materials Science,
  • Graduate School of Frontier Sciences,
  • The University of Tokyo
  • Kashiwanoha 5-1-5,
  • Kashiwa,Chiba 277-8561, Japan
  • harada@issp.u-tokyo.ac.jp