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Updated: Apr 6, 2026
Compact Quantum Dots for Single-molecule Imaging
Published on: October 9, 2012
Nanoscale optical positioning of single quantum dots for bright and pure single-photon emission
Luca Sapienza1, Marcelo Davanço2, Antonio Badolato3
11] Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA [2] Maryland NanoCenter, University of Maryland, College Park, Maryland 20742, USA [3] School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK.
Abstract:
Self-assembled, epitaxially grown InAs/GaAs quantum dots (QDs) are promising semiconductor quantum emitters that can be integrated on a chip for a variety of photonic quantum information science applications. However, self-assembled growth results in an essentially random in-plane spatial distribution of QDs, presenting a challenge in creating devices that exploit the strong interaction of single QDs with highly confined optical modes. Here, we present a photoluminescence imaging approach for locating single QDs with respect to alignment features with an average position uncertainty <30 nm (<10 nm when using a solid-immersion lens), which represents an enabling technology for the creation of optimized single QD devices. To that end, we create QD single-photon sources, based on a circular Bragg grating geometry, that simultaneously exhibit high collection efficiency (48%±5% into a 0.4 numerical aperture lens, close to the theoretically predicted value of 50%), low multiphoton probability (g(2)(0) <1%), and a significant Purcell enhancement factor (≈3).
