Bright quantum dot light sources using monolithic microlenses on gold back-reflectors

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

We demonstrate a scalable method for fabricating bright GaAs quantum dot (QD) photon sources by embedding them into broadband monolithic AlGaAs microlens arrays on gold-coated GaAs substrates. Cylindrical photoresist templates (2-5 µm diameter) are thermally reflowed and transferred into AlGaAs thin films using an optimized 3D reactive ion etching process. This yields large-area (2 mm × 4 mm), high-density (∼ 40 × 10 3 mm−2) microlens arrays of uniform shape. The brightest QD emissions are found in lenses with 2.7 µm diameter and 1.35 µm height. Finite-difference time-domain simulations of lens geometries reveal optimization potentials, including anti-reflection coatings. It is found that free-space and fiber-coupled extraction efficiencies can reach up to 62% and 37%, respectively. A statistical fabrication model, validated through photoluminescence spectroscopy, shows intensity enhancements up to × 200 in ca. 1 out of 200 lenses, aligning well with theoretical predictions. This approach highlights the promise of compact, efficient photon sources for future large-scale quantum network applications.

Details

Original languageEnglish
Article number225301
JournalNanotechnology
Volume36
Issue number22
Publication statusPublished - 2 Jun 2025
Peer-reviewedYes

External IDs

PubMed 40315872
ORCID /0000-0001-8469-9573/work/203069097

Keywords

Keywords

  • 3D-micro engineering, nanophotonics, quantum dots, quantum light sources, semiconductor Heterostructures