Mikio Yamashita

Noncollinear Optical Parametric Amplification Pumped by the Third Harmonics of a Ti:sapphire Laser

Broardband amplification in the 380-490 nm region was achieved by ultraviolet (UV) pumped noncollinear optical parametric amplification. This result leads to 6 fs UV pulse generation and can be utilized to amplify monocycle pulses.

Femtosecond Photoisomerization Study on Azobenzene-Derivative Bound by DNA

First observation of femtosecond absorbance change in azobenzene-derivative (AzD) bound by double-strand DNA, that by single-strand DNA and Azd shows trans-to-cis photoisomerization rate per pulse in the former is much lower than in the latter.

Generation of Ultrashort Optical Pulses Using Multiple Coherent Anti-Stokes Raman Scattering Signals in a Crystal and Observation of the Raman Phase

We demonstrate Fourier synthesis of the multiple coherent anti-Stokes Ramanscattering signals in LiNbO3. Both angle and temporal dispersions of the signals are compensated for by a modified 4f configuration. As a result, isolated pulses with 25-fs duration (640-780 nm) are generated and discrete phase shifts due to Raman coherence are observed.

Simultaneous coherent multicolor pulse shaping using two-dimensional spatial light amplitude- and phase-modulator for multi-selective wave-packet control

Using a two-dimensional spatial light amplitude and phase-modulator, simultaneous multicolor pulse shaping of coherent ultrabroadband (600 to 850 nm) optical pulses generated by self-phase modulation in an Ar-gas filled fiber, being applicable for multicolor coherent wave-packet control, was demonstrated.

Femtosecond Optical Pulse Propagation in Highly Nonlinear Doped-Silica Single-Mode Fibers

Performing both the experiment and calculation of nonlinear femtosecond optical-pulse propagation in GeO2-doped and Er:GeO2-doped silica single-mode fibers, we determined nonlinear refractive indices n2 and delayed nonlinear response times TR to be given by n2,GeO2doped = 3.5 x 10^-13 esu, TR,GeO2doped = 1.8 fs, n2,Er:GeO2doped = 1.1 x 10^-12 esu, and TR,Er:GeO2doped = 2.1 fs.