Site-Selective, Two-Photon Plasmonic Nanofocusing on a Single Quantum Dot for Near-Roomerature Operation

Su Hyun Gong, Sejeong Kim, Je Hyung Kim, Jong Hoi Cho, Yong Hoon Cho

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Although the study of single quantum dot (QD) properties without the background noise and dephasing processes caused by surrounding carriers is a crucial issue, the spatial-selective excitation of a single QD is still challenging, due to the diffraction nature of light. Here, we demonstrate a deep subwavelength excitation of a single QD using two-photon plasmonic nanofocusing. Self-aligned plasmonic nanofocusing on a single QD was achieved using metal coated nanopyramid structures. The highly enhanced local electric field generated by the plasmonic nanofocusing gives rise to a large increase in the optical nonlinear effect (i.e., two-photon excitation). As a result of the enhanced field enhancement on the metal-pyramid hybrid structure, the two-photon luminescence intensity was enhanced by a factor of 5000, and the selective excitation of a single QD enabled us to observe InGaN QD emission at near room temperature, due to the large suppression of the background emission. Our approach opens promising perspectives for quantum optics experiments with highly reduced background emissions.

Original languageEnglish
Pages (from-to)711-717
Number of pages7
JournalACS Photonics
Issue number3
Publication statusPublished - 2018 Mar 21
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation (NRF) grant funded by the Korea government (NRF-2016R1A2A1A05005320) and Samsung Science and Technology Foundation under Project Number SSTF-BA1602-05.

Funding Information:
*E-mail: Tel.: +82-42-350-2549. Fax: +82-42-350-5549. ORCID Su-Hyun Gong: 0000-0002-8652-714X Je-Hyung Kim: 0000-0002-6894-9285 Yong-Hoon Cho: 0000-0002-7701-8562 Present Address †Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea Notes The authors declare no competing financial interest.

Publisher Copyright:
© 2018 American Chemical Society.


  • Self-aligned plasmonic nanofocusing
  • nonlinear
  • single quantum dot spectroscopy
  • site-controlled quantum dot
  • two-photon excitation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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