Quantum Dots Luminescence Collection Enhancement and Nanoscopy by Dielectric Microspheres

Francesco Biccari*, Travis Hamilton, Andrea Ristori, Stefano Sanguinetti, Sergio Bietti, Massimo Gurioli, Hooman Mohseni

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


In recent years, dielectric microspheres have been used in conjunction with optical microscopes to beat the diffraction limit and to obtain superresolution imaging. The use of microspheres on quantum dots (QDs) is investigated, for the first time, to enhance the light coupling efficiency. The enhancement of the QD luminescence collection in terms of extraction and directionality is demonstrated, as well as the enhancement of spatial resolution. In particular, it is found that a dielectric microsphere, placed on top of an epitaxial QD, increases the collected radiant energy by about a factor of 42, when a low numerical aperture objective is used. Moreover, if two or more QDs are present below the microsphere, the modification of the far field emission pattern allows selective collection of the luminescence from a single QD by simply changing the collection angle. Dielectric microspheres present a simple and efficient tool to improve the QD spectroscopy, and potentially QD-based devices.

Original languageEnglish (US)
Article number1900431
JournalParticle and Particle Systems Characterization
Issue number1
StatePublished - Jan 1 2020


  • microspheres
  • near field
  • photoluminescence
  • photonic nanojet

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics


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