| Project/Area Number |
07044121
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | University of Tokyo |
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Principal Investigator |
KUWATA-GONOKAMI Makoto Graduate school engineering, University of Tokyo, Associate Professor, 大学院・工学系研究科, 助教授 (70161809)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMANO Ryo Graduate school engineering, University of Tokyo, 大学院・工学系研究科, 助手 (40262042)
HANAMURA Eiichi Graduate school engineering, University of Tokyo, 大学院・工学系研究科, 教授 (70013472)
MAZUMDAR Sum Department of Physics, University of Ariz, 準教授
PEYGHAMBARIAN Nasser Optical Sciences Center, University of Arizona, University of Ar, 教授
MAZUMDAR Sumitendra Department of Physics, University of Arizona
SUMITENDRA M Department of Physics, University of Ariz, 準教授
NASSER Peygh Optical Sciences Center, University of Ar, 教授
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1996: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | exciton-strings / charge transfer exciton / photo induced conductivity / biexciton / nonlinear optics / フェムト秒分光 / 非古典光 |
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| Research Abstract |
In this program, the research members of University of Tokyo and university of Arizona study the optical phenomena in quasi one-dimensional charge transfer (CT) crystals where collective Coulomb interaction plays an essential role.
First we study the multi-exciton states which are formed by the strong photo-excitation of neutral CT excitons. High density excitation of charge transfer excitons by sub-picosecond light pulses generate multi-exciton chains along the stack axis of the crystal. We theoretically examined the condition to stabilize the multi exciton states. By the numerical calculation we examined the shape of wave functions of multi exciton states. We found that the nonclassical light emission could occur when such multi excitons are embedded in a microcavity.
Secondly, we study a new type of photo-induced carrier transport phenomena in ANT-PMDA.We apply static electric field parallel to the stack axis of a thin single crystal at liquid helium temperature and illuminate it with monochromatic light tuned to the zero phonon line of the CT-exciton. By making the image of the crystal with the DC-Stark effect, we can draw the electric field distribution. With the additional photo-excitation on the crystal, a "hole" of the electric field appears just on the spot of the photo-irradiation. This "hole" is created only when the photon energy of the beam is tuned above the exciton absorption edge. With the assistance of the photo-excitation, carriers move along the stack axis and stay at the edge of the illuminated region. They eventually cancel the external field. A self trapped residual electron or hole attracts a photo generated CT-exciton and forms a coupled state A^-D^+A^-. Successive annihilation of the CT exciton results in the charge transport along the stack axis. To explore the microscopic mechanism of this exciton mediated carrier transport phenomena, we will continue the collaboration.
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