Molecular vibrational modes exist in the mid/far-infrared spectral range. We can study the functional groups, the molecular structure, and the strength of intra/inter-molecular hydrogen bonding by infrared and/or Raman spectroscopy. Time-resolved vibrational spectroscopy, by use of infrared optical pulses, can potentially elucidate the molecular dynamics of vibrational relaxation, proton transfer, isomerization, etc. Molecular dynamics in hydrogen-bonded systems (e.g. DNA, protein, and water) are of great importance in understanding the mysteries of life. Recent studies have started to reveal that the vibrational relaxation in the condensed phases typically occurs in 100 fs time-scale. In order to investigate and to control such ultrafast molecular dynamics with high time-resolution, further developments in generation/control of infrared light pulses are necessary.
  　The objectives of the research are the development of novel ultrashort pulse generation/control techniques in the mid-infrared spectral range, and their application to ultrafast molecular vibrational spectroscopy. Based on broadband frequency conversion via second-order nonlinearity and the infrared dispersion compensation, I aim to generate extremely short infrared pulses with a few optical cycle and micro-joule pulse energy. In addition, the arbitrary pulse shaping technique will be developed in this frequency region. By using such ultrashort infrared pulses, I will develop nonlinear vibrational spectroscopy system. It will enable us to investigate the molecular vibrational dynamics in the condensed phases with high time-resolution. Anharmonic couplings between different modes will also be revealed with high sensitivity. The techniques and the knowledge accumulated in this study can contribute to various applications, including quantum control on vibrational dynamics.