ISSP - The institute for Solid State Physics

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Itatani Group
Associate Professor
ITATANI,
Jiro

Research Associate
ISHII,
Nobuhisa

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Development of phase-stable intense ultrashort-pulse lasers and their applications to attosecond and strong-field physics are the main subjects of our research. As for the light source, we develop waveform-controlled intense optical pulses in IR and mid-IR spectral regions. Currently, several state-of-art IR and mid-IR sources are operational to produce high harmonics in gas or solids. For the spectroscopic applications, we develop new methods using waveform-controlled strong optical fields and attosecond pulses to explore field-induced ultrafast processes of atoms, molecules, and condensed matters. We focus on field-driven electron dynamics and related nonlinear phenomena (e. g., high harmonic generation) in solids using intense mid-IR sources. Our methodology is based on the cutting-edge light sources and their frequency conversion to cover the spectral range from terahertz to soft X rays with precise synchronization. We aim to use such extremely broadband and ultrafast coherent light sources for observing and controlling the quantum dynamics of non-equilibrium states of matters through various freedoms.

(a)Soft-X-ray spectra of high harmonics from neon (blue curve) and helium (red curve) that cover the water window. (b) CEP dependence of the high harmonic spectra from helium. The phase-dependent structure shows the generation of isolated attosecond pulses around a photon energy of 450 eV.
High harmonic spectra from a semiconductor GaSe produced by linearly (blue curve) and circularly (red curve) polarized mid infrared light. In the case of circularly polarized input, the high harmonic spectrum obeys the selection rule.

Research Subjects

  1. Development of intense ultrashort-pulse lasers
  2. Attosecond physics
  3. Ultrafast spectroscopy and coherent control of photo-induced dynamics in atoms, molecules, and solids
  4. Soft-X-ray ultrafast spectroscopy of molecules and solid