Browsing by Author "Miyanaga, Noriaki"

Now showing 1 - 3 of 3

Sub-15fs ultraviolet pulses generated by achromatic phase-matching sum-frequency mixing
(2009-09-28)
Zhao, Baozhen
;
Jiang, Yongliang
;
Sueda, Keiich
;
Miyanaga, Noriaki
;
Kobayashi, Takayoshi
A broadband ultraviolet pulse with a spectral width of 44 nm was generated by achromatic sum-frequency mixing of an 805-nm pulse and ultrabroadband visible pulse. Angular dispersion was introduced to achieve broadband phase matching by a prism pair. The UV pulse was compressed to 13.2 fs with another prism pair, with energy of 600 nJ. (C) 2009 Optical Society of America
Ultrabroadband noncollinear optical parametric amplification with LBO crystal
(2008-11-10)
Zhao, Baozhen
;
Jiang, Yongliang
;
Sueda, Keiich
;
Miyanaga, Noriaki
;
Kobayashi, Takayoshi
Ultrabroadband visible noncollinear optical parametric amplification (NOPA) was achieved in an LBO crystal, with a continuum seed pulse generated from a sapphire plate. The spectral bandwidth of the amplified visible pulse was about 200 nm, which can support sub-5 fs pulse amplification. An amplified output of 0.21 uJ with an average gain of about 210 was achieved. This provides, to the best of our knowledge, the first-time demonstration of such broadband amplification with a biaxial nonlinear optical crystal. Both the simulation and experimental results indicate that the LBO has a great potential as nonlinear medium in power amplifier for TW to PW noncollinear optical parametric chirped pulse amplification (NOPCPA) systems. (C) 2008 Optical Society of America
Ultrafast Time-Resolved Pump-Probe Spectroscopy of PYP by a Sub-8 fs Pulse Laser at 400 nm
(2013-05-02)
Liu, Jun
;
Yabushita, Atsushi
;
Taniguchi, Seiji
;
Chosrowjan, Haik
;
Imamoto, Yasushi
Impulsive excitation, of molecular vibration is known to induce wave packets in both the ground state, and excited State. Here, the ultrafast dynamics of PIP was studied by pump probe spectroscopy using a sub-8 fs pulse laser at 400 nm. The broadband spectrum of the UV pulse allowed us to detect the pump probe signal covering 360-440 nm. The dependence of the vibrational phase of the vibrational mode around 1155 cm(-1) on the probe photon energy was observed for the first time to our knowledge. The vibrational mode coupled to the electronic transition observed in the probe spectral ranges of 2.95-3.05 and 3.1573.35 eV was attributed to the. wave packets in the ground state and the excited state, respectively.: The frequencies in the ground state and excited state were determined: to be 1155 +/- 1 and 1149 +/- 1 cm(-1), respectively. The frequency difference is due to change after photoexcitation; This means a reduction of the bond strength associated with pi-pi* excitation, :which is related to the molecular structure. change associated with the primary isomerization process in the photocycle in PYP. Real time vibrational modes at low frequency around 138, 179, 203, 260, and 317 cm(-1) were also observed and compared with, the Raman spectrum for the assignment of the vibrational wave packet.