EXTREME COHERENT OPTICAL SCIENCE
KOZO OKAZAKI LAB.
INTRODUCTION OF LABORATORY
Angle-resolved photoemission spectroscopy is a very powerful experimental technique that can directly observe a dispersion relation between momentum and energy of the electrons in solid-state materials, whereas by utilizing a femtosecond laser as pumping light and its high harmonic generation as probing light, we can observe ultrafast transient properties of the band structures in a non-equilibrium state. In our group, we are developing and improving a time-resolved photoemission apparatus that utilize high harmonic generations of an ultrashort-pulse laser in collaboration with a laser-developing group. We are aiming for understanding the mechanisms of electron relaxations from photo-excited states and mechanisms of photo-induced phase transitions by direct observations of transient electronic states with a pump-probe type time-resolved photoemission spectroscopy. Also, we are aiming for understanding the mechanisms of unconventional superconductivity by direct observations of the electronic structures and superconducting-gap structures of unconventional superconductors with a laser-based angle-resolved photoemission apparatus with a world-record performance that achieves a maximum energy resolution of 70 micro eV and lowest cooling temperature of 1 K.
高次高調波レーザーを用いた時間分解光電子分光装置の概略図
高次高調波レーザー時間分解光電子分光で観測された励起子絶縁体Ta2NiSe5における光誘起絶縁体-金属転移 a,bはそれぞれ、光励起前、光励起後のスペクトル
MESSAGE
IF YOU WORK ON YOUR RESEARCH WITH CURIOSITY AND SHOW INTEREST IN ANYTHING, YOU CAN DEFINITELY FIND A TREMENDOUS NUMBER OF DISCOVERIES. NEVER GIVE UP, AND THEN A BRIGHT FUTURE WILL OPEN FOR YOU.
When I was an elementary school student, The Inter-national Science Exposition was held at Tsukuba (Expo ’85). In one of the events for the Expo., I posted a letter into the “post capsule”, in which posted letters will be sent back to oneself 16 years later. In that letter, I had written my dream for the future; that is, what I want to be when I grow up. Completely forgotten such a thing, I had devoted myself to kendo during the elementary and junior high school, got interested in theories of relativity and elementary particles in high school, and majored in physics at University of Tokyo. Even at that time, I had not yet imagined I would become a scientist. However, I was attracted by the studies with a professor in the graduate school, and had gone to the doctor course unexpectedly. I think my exciting experiences and intellectual curiosity motivated my research life. Now, I would like to return the favor to my respected professors and prepare better environment for younger scientists to continue with their studies. From the “post capsule”, the letter came back to me having continued with study 16 years later. There has been written that “I want to be a scientist when I grow up.” My dream I described as a child has come true. When I was a primary school student, I could see my future, couldn’t I?!
keyword
Electron-lattice interaction / Superconductivity / Transition metal dichalcogenides / Time-resolved ARPES / Charge density waves / Exciton insulators / Nonequilibrium electronic states / Coherent phonons / Photo-induced phase transition / Time-resolved photoelectron spectroscopy / Optical system development / Photoelectrons Light source development for spectroscopy / High temperature superconductivity / Raman spectroscopy / Infrared spectroscopy / Isotope substitution / Oxygen isotope effect / Optical conductivity / Oxide high temperature superconductor
PROFILE : Associate Professor Kozo Okazaki
1998 B. Sc., Department of Physics, University of Tokyo
2003 Dr. Sc., Department of Physics, University of Tokyo
2003 Researcher, Institute for Solid State Physics, University of Tokyo
2003 Assistant Professor, Department of Physics, Nagoya University
2010 Researcher, Institute for Solid State Physics, University of Tokyo
2013 Assistant Professor, Department of Physics, University of Tokyo2014
2014 Project Associate Professor, Institute for Solid State Physics, University of Tokyo
2019 Associate Professor, Institute for Solid State Physics, University of Tokyo
STUDENT VOICE : TAKESHI SUZUKI
Professor Okazaki has an pioneering research record in the world, which primarily focuses on superconductivities e.g. mechanisms for iron-based superconductors. Moreover, he has deep knowledge and broad perspective over the significantly wide area in the condensed matter as well as optics. He is very busy, but always takes time for us to discuss until we are completely satisfied. The lab has two state-of-the-arts apparatus with their quite different characters. We can use both of them and discover many new phenomena emergent in a condensed matter for the frst time in the world. Through valuable experimental data and intensive discussions, we are always surprised to encounter elegant secrets which nature hide from us until then.
SOLID STATE PHYSICS AND CHEMISTRY
The important thing when doing research is to have “curiosity” and “interest.”
Kozo Okazaki Lab.,
Department Of Advanced Materials Science,
Graduate School of Frontier Sciences,
The University of Tokyo
Kashiwanoha 5-1-5,
Kashiwa,Chiba 277-8561, Japan
+81-4-7136-3355
okazaki@issp.u-tokyo.ac.jp
The Goal of Applied Physics
The goal of Applied Physics is to develop a stage = “new material” that can manipulate undeveloped degrees of freedom, to explore unknown phenomena created from that stage and to bring out excellent functions, and to bring out its excellent functions. The purpose is to contribute to the development of human society by elucidating the mechanisms and developing application fields for these phenomena and functions.
AMS (Advanced Materials Science)
Department Office
AMS (Advanced Materials Science),
Graduate School of Frontier Sciences,
The University of Tokyo
Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8561, Japan
Email : ams-office(at)ams.k.u-tokyo.ac.jp
Please change (at) to @.