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Hamaguchi Lab.

Spectrophysical Chemistry bridges chemistry and biology


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Femtosecond Time-Resolved Near-Infrared Spectroscopic System

Femtosecond Time-Resolved Near-Infrared Spectroscopic System

Fig. 1

Fig. 1. Apparatus

  • The second harmonic of the output of a Ti:sapphire regenerative amplifier (395nm, 1kHz, 200fs) is used as the pump light. The white light obtained by the self-phase modulation with the same amplifier output on a sapphire plate is used as the probe light.
  • Two sets of near-infrared polychromators and InGaAs array detectors (256 channel) are used for recording reliable time-resolved near-infrared spectra. Spectral coverage of the polychoromator is 900-1500nm.
Fig. 2

Fig. 2. Femtosecond time-resolved near-infrared spectroscopic System. Pulse duration ∼200fsAExcitation wavelength 395nm


Fig. 3

}3: Titanium dioxide

Fig. 4

}4: Diagram

Titanium dioxide (TiO2)
  • White powders
  • When TiO2 is photoirradiated, electrons and holes are generated. They eventually oxidize or reduce the reactants on the surface of the TiO2 particles.
  • Direct absorption measurements with NIR. In the near-infrared region, transmittance of TiO2 is large facilitating the direct transmission measurement of absorption.
Femtosecond time-resolved near-infrared study
Transmission measurement is possible in the near-infrared region (900-1600nm).
We can measure the early-stage dynamics of charge carriers photogenerated in the TiO2 powders.

Results (Time-resolved near-infrared absorption spectra)

Fig. 5

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