| Project/Area Number |
05452066
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
物理学一般
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
GONOKAMI Makoto The University of Tokyo, Faculty of Engineering, Department of Applied Physics, Associate Professor, 大学院・工学系研究科, 助教授 (70161809)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SHIMANO Ryo The University of Tokyo, Faculty of Engineering, Department of Applied Physics,, 大学院・工学系研究科, 助手 (40262042)
江馬 一弘 東京大学, 工学部, 助手 (40194021)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Project Status |
Completed (Fiscal Year 1994)
|
| Budget Amount *help |
¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1994: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1993: ¥4,600,000 (Direct Cost: ¥4,600,000)
|
|---|
| Keywords | exciton / biexciton / nonlinear optics / four-wave-mixing / micro cavity / polariton / exciton strings / coherence / 励起子コヒーレンス / 表面励起子 / 位相共役波 / 2光子コヒーレンス / フェムト秒分光 / 励起子超放射 / 量子井戸励起子 / 巨視的位相 / ボーズ凝縮 / 非線形干渉法 / モット転移 |
|---|
| Research Abstract |
In order to explore the mechanism of ultrafast coherent third order nonlinear responses in solid materials, we have developed a method to detect the coherent motion of macroscopic polarization created by the optical excitation. By this method, we can investigate phase coherence of resonantly excited excitons and biexcitons in inorganic and organic materials.
1)Nonlinear Interferometer
We have proposed a scheme to measure the coherence of third-order nonlinear polarization by detecting the interference of degenerate four-wave mixing signal and reference optical pulses which were also from the same light source used to create coherent excitation of nonlinear polarization. With this set-up, we have detected the coherent oscillation of nonlinear polarization.
2)Observation of Coherent Oscillation of Biexcitons in CuCl
The coherent oscillation of biexcitons under the resonant two-photon excitation by femtosecond pulses has shown that the coherent oscillation continues up to 50 picosecond.
3)Inte
… More
rference of Scalar Biexciton Waves
We have observed the interference of two biexciton waves which were excited by the orthogonally polarized pump beams. This indicates that the biexciton wave has the scalar wave nature. This is, to the best of our knowledge, the first time observation of scalar wave interference in solids.
4)Detection of two-exciton coherence in GaAs quantum well
We have applied the above methods to the 2D quantum well excitons which do not have stable biexciton state. We have clearly observed 2-f coherent oscillation which decays within 3 picosecond.
5)Free Induction Decay of 2D Excitons in Anthracence crystals
By using the coherent pump-probe spectroscopy, we have observed coherent oscillation signal of surface excitons in an anthracence crystal. We have examined the role of cooperative radiation decay of surface excitons, which is known as superradiative decay of 2D excitons.
6)Degenerate Four Wave Mixing of Exciton-Cavity Coupled System
We have studied the linear exciton-photon coupling effect on the coherent nonlinear optical responses of excitons in 2D quantum well embedded in a semiconductor microcavity. We have observed that the strong confinement of photons inside the cavity enhances the coherent noonlinear responses. In the case of strong exciton-photon coupling, the formation of cavity polartons affects the coherent oscillation of excitonic polarization. We have developed a theoretical model to describe such phenomena based on the weakly interacting boson model. Less
|
