ISSP - The institute for Solid State Physics

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Okazaki Group
Project Associate Professor

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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 (HHG) 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 utilizes high harmonic generation of an ultrashort-pulse laser in collaboration with laser development groups, and aiming for understanding the mechanisms of electron relaxations from photo-excited states and demonstration of light-induced superconductivity by direct observations of transient electronic states using pump-probe type time-resolved photoemission spectroscopy (TrPES). In addition, 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 μeV and lowest cooling temperature of 1 K.

Schematic diagram of a time-resolved photoemission apparatus utilizing a femtosecond laser and its high harmonic generation.
Coherent phonon excitation in BaFe2As2 observed by HHG TrPES.

Research Subjects

  1. Development of a time-resolved photoemission apparatus utilizing high harmonic generation from a ultrashort-pulse laser
  2. Mechanisms of electron relaxation from photo-excited states and light-induced superconductivity
  3. Mechanisms of unconventional superconductivities by ultralow temperature and ultrahigh resolution laser-based angle-resolved photoemission spectroscopy