| Budget Amount *help |
¥24,310,000 (Direct Cost: ¥18,700,000、Indirect Cost: ¥5,610,000)
Fiscal Year 2015: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2014: ¥10,270,000 (Direct Cost: ¥7,900,000、Indirect Cost: ¥2,370,000)
Fiscal Year 2013: ¥9,620,000 (Direct Cost: ¥7,400,000、Indirect Cost: ¥2,220,000)
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| Outline of Final Research Achievements |
We successfully observed electronic oscillation with attosecond (as: 10^-18 sec.) periodicity with gallium nitride (GaN) semiconductor using an isolated attosecond pulse (IAP). A near-infrared pulse induces the electric interband polarization. The oscillation with 860-as periodicity in the GaN electron and hole system is revealed by the IAP. The resultant frequency reaches 1.16 PHz (10^15 Hz), making the first time the petahertz frequency barrier has been exceeded with semiconductor.
In addition, we observed an inner-shell electron motion using the IAP. We were able to characterize it by combining the IAP and an analytical method called SPIDER (spectral phase interferometry for direct electric-field reconstruction). The method can fully characterize the dipole response (the decay time, dipole phase, and dipole oscillation).
These studies on the ultrafast electron motion are substantially importance for future quantum optics, chemistry, and high-speed signal processing engineering.
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