Photonic Jet Writing of Quantum Dots Self-Aligned to Dielectric Microspheres

Andrea Ristori, Travis Hamilton, Dimosthenis Toliopoulos, Marco Felici, Giorgio Pettinari, Stefano Sanguinetti, Massimo Gurioli, Hooman Mohseni, Francesco Biccari*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Owing to their ability to generate non-classical light states, quantum dots (QDs) are very promising candidates for the large-scale implementation of quantum information technologies. However, the high photon collection efficiency demanded by these technologies may be impossible to reach for “standalone” semiconductor QDs, embedded in a high-refractive index medium. In this work a novel laser writing technique is presented, enabling the direct fabrication of a QD self-aligned—with a precision of ±30 nm—to a dielectric microsphere. The presence of the microsphere leads to an enhancement of the QD luminescence collection by a factor 7.3 ± 0.7 when an objective with 0.7 numerical aperture is employed. This technique exploits the possibility of breaking the N−H bonds in GaAs (Formula presented.) Nx:H by a laser light, obtaining a lower-bandgap material, GaAs (Formula presented.) Nx. The microsphere, deposited on top of a GaAs (Formula presented.) Nx:H/GaAs quantum well, is used to generate a photonic nanojet, which removes hydrogen exactly below the microsphere, creating a GaAs (Formula presented.) Nx QD at a predefined distance from the sample surface. Second-order autocorrelation measurements confirm the ability of the QDs obtained with this technique to emit single photons.

Original languageEnglish (US)
Article number2100045
JournalAdvanced Quantum Technologies
Issue number9
StatePublished - Sep 2021


  • collection enhancement
  • dilute nitrides
  • microspheres
  • photonic jets
  • site-controlled quantum dots

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics
  • Statistical and Nonlinear Physics
  • Electronic, Optical and Magnetic Materials
  • Computational Theory and Mathematics
  • Mathematical Physics
  • Electrical and Electronic Engineering


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