Makoto Nakajima

Institute of Laser Engineering, Osaka University
Associate Professor

Research AreasTerahertz engineering, Ultrafast spectroscopy, Optical properties of solid
Participating Group (2018-2019)

Ultrafast terahertz switching in organic bistable material

Terahertz, Optical control, Photo-induced phase transition, Ultrafast spectroscopy, Bi-stable memory, metamaterial
Co-Researcher: Tatsunosuke Matsui (Faculty of Engineering, Mie University, Associate Professor)

Research Outline

Recent progress of the research using the terahertz pulses is very significant. Many researches by using terahertz pulses were performed such as spectroscopy, terahertz pump induced phenomena, and nonlinear optic effect. Figure 1 shows the observed terahertz waveforms in time domain with the peak amplitude of electric field (500kV/cm) and magnetic field (0.15 Tesla). Use of the terahertz pulse excitation with high intensity enable us to examine ultrafast optical control for the material states and phases. Figure 2 shows our recent experimental results for the coherent control of the magnetic state for ErFeO3 using terahertz pulse excitation around the spin reorientation phase transition (PRL 120, 107202, (2018).). Our purpose of this study is demonstration of the ultrafast switching for the conductivity states for the solids such as organic materials, soft crystals, and bi-stable materials which are very sensitive to the stimuli such as external electric and magnetic field, and optical excitation.

Terahertz waveform with the peak amplitude of electric field of 500kV/cm and magnetic field of 0.15 Tesla, and the Fourier-transformed spectrum.
Ultrafast coherent control of the magnetic state by terahertz pulse excitation.


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