Unidirectional signal transfer in quantum-dot systems via optical near-field interactions

W. Nomura, T. Yatsui, T. Kawazoe, M. Naruse, N. Tate, M. Ohtsu

Research output: Chapter in Book/Report/Conference proceedingConference contribution


To decrease the sizes of photonic devices beyond the diffraction limit of light, we propose nanophotonic devices based on optical near-field interactions between semiconductor quantum dots (QDs). To drive such devices, an optical signal guide whose width is less than several tens of nanometers is required. Furthermore, unidirectional signal transfer is essential to prevent nanophotonic devices operating incorrectly due to signals reflected from the destination. For unidirectional signal transfer at the nanometer scale, we propose a nanophotonic signal transmitter based on optical nearfield interactions between small QDs of the same size and energy dissipation in larger QDs that have a resonant exciton energy level with the small QDs. To confirm such unidirectional energy transfer, we used time-resolved photoluminescence spectroscopy to observe exciton energy transfer between the small QDs via the optical near-field, and subsequent energy dissipation in the larger QDs. We estimated that the energy transfer time between resonant CdSe/ZnS QDs was 135 ps, which is shorter than the exciton lifetime of 2.10 ns. Furthermore, we confirmed that exciton energy did not transfer between nonresonant QD pairs. These results indicated that the proposed nanophotonic signal transmitters based on optical near-field interactions and energy dissipation could be used to make multiple transmitters and selfdirectional interconnections.

Original languageEnglish
Title of host publicationPlasmonics
Subtitle of host publicationMetallic Nanostructures and Their Optical Properties VI
Publication statusPublished - 2008
Externally publishedYes
EventPlasmonics: Metallic Nanostructures and Their Optical Properties VI - San Diego, CA, United States
Duration: Aug 10 2008Aug 14 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherPlasmonics: Metallic Nanostructures and Their Optical Properties VI
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Applied Mathematics
  • Electrical and Electronic Engineering
  • Computer Science Applications


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