Bright quantum dot light sources using monolithic microlenses on gold back-reflectors
Year: 2025
Type: article
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.
Source: Nanotechnology
Authors: Moritz Langer, Sai A Dhurjati, Yared G Zena, Ahmad Rahimi, Mandira Pal, Liesa Raith, Sandra Nestler, Riccardo Bassoli, Frank H P Fitzek, Oliver G Schmidt, Caspar Hopfmann
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
OpenAlex ID: W4410022655