Cryogenic photoluminescence imaging system for nanoscale positioning of single quantum emitters

TL;DR

This paper introduces a cryogenic photoluminescence imaging system capable of locating single quantum emitters with nanometer precision, facilitating the assembly of nanophotonic devices by accurately positioning quantum dots.

Contribution

The system allows high-precision localization of quantum dots within a cryostat using a high NA objective, achieving approximately 4.5 nm uncertainty in a 1-second acquisition, which is novel for cryogenic conditions.

Findings

Achieved ~4.5 nm localization precision of quantum dots.

Enabled high-efficiency photon collection at cryogenic temperatures.

Demonstrated potential for high-throughput nanophotonic device fabrication.

Abstract

We report a photoluminescence imaging system for locating single quantum emitters with respect to alignment features. Samples are interrogated in a 4~K closed-cycle cryostat by a high numerical aperture (NA=0.9, 100$\times$ magnification) objective that sits within the cryostat, enabling high efficiency collection of emitted photons without image distortions due to the cryostat windows. The locations of single InAs/GaAs quantum dots within a $>50$~$\mu$m~$\times$~50~$\mu$m field of view are determined with $\approx4.5$~nm uncertainty (one standard deviation) in a 1~s long acquisition. The uncertainty is determined through a combination of a maximum likelihood estimate for localizing the quantum dot emission, and a cross-correlation method for determining the alignment mark center. This location technique can be an important step in the high-throughput creation of nanophotonic devices that rely upon the interaction of highly confined optical modes with single quantum emitters.