The 85th KARC Colloquium
The 85th KARC Colloquium was ended. Thank you for the participation.
| Date&Time | Tuesday, August 21, 2007 14:00-15:00 |
| Place | Conference Room, 3F, Research Building 2,Advanced ICT Research Center |
| Lecturer | "Surface electromagnetic wave coupled emission of CdSe/ ZnS quantum dots located near the dielectric interface " |
| Speaker | Dr. Ryo Naraoka （Nanophotonics Laboratory, RIKEN) |
| Abstracts | Recently, single molecule fluorescence detection with surface electromagnetic wave coupling emission has attracted a great deal of interest, because it can be utilized for the analysis of the three dimensional conformational change of a single bio-molecule. In this method, the enhancements of the evanescent surface electromagnetic fields are utilized for both the excitation and the radiation of the dipole near the interface. CdSe/ ZnS quantum dots have the high quantum yields and stability compared with usual organic dye molecules. However, the transition dipole moment of CdSe/ ZnS QD is quite different from that of usual organic dye molecule due to its wurtzite crystal structure, and it is necessary to consider the particular two dimensionally degenerated transition dipole moment of CdSe/ ZnS QD for the analysis. We studied the radiative decay mechanism of the single CdSe/ ZnS QDs placed on the air-dielectric interface. In order to reveal the radiative decay characteristics of 2D degenerated transition dipole moment of CdSe/ ZnS QDs, we measured both fluorescence lifetime and defocused radiation pattern for each QD. Theoretical calculations reveal the role of photonic mode density and the orientational dependence for 2D degenerated dipoles near the interfaces, and it was appeared that the decay rates for single QDs couldn’t be expressed as the simple summation of two orthogonal linear dipoles. Consequently we present the surface electromagnetic wave coupled emission properties for the single CdSe/ ZnS QDs located near the dielectric interfaces. |
| Language | Japanese |
| Admission | Free |
| Organizer | Dr. Akira Otomo, Nano-ICT group, Advanced ICT Research Center,National Institute of Information and Communications Technology |