| Budget Amount *help |
¥17,810,000 (Direct Cost: ¥13,700,000、Indirect Cost: ¥4,110,000)
Fiscal Year 2010: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2009: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2008: ¥11,310,000 (Direct Cost: ¥8,700,000、Indirect Cost: ¥2,610,000)
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| Research Abstract |
We have demonstrated that the phase-controlled terahertz radiation can be generate by the burst current produced by a laser created ionization front, which is induced an optical-field-induced ionization (OFI) in air with a pulsed electric field. The peak frequency of the radiation spectrum depends on the rise time of the OFI. The central frequencies of the radiation were observed to be 0.3 and 0.1 THz at the pulse durations of 30 and 100 fs (FWHM), respectively. We also have demonstrated the proof-of-principle experiment of flash ionization scheme using the interaction between a terahertz wave and plasmas created by an ultrashort laser pulse. When plasmas were instantaneously created around an electromagnetic wave, frequency of the wave up-converted to the frequency, which depended on the plasma frequency. We observed frequency up-conversion from 0.35 THz to 3 THz by the irradiance of the laser in ZnSe crystal.
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