Sub-Wavelength Multi-Channel Imaging Using a Solid Immersion Lens: Spectroscopy of Excitons in Single Quantum Dots

TL;DR

This paper presents a method for sub-wavelength imaging of excitons in single quantum dots using a solid immersion lens, enabling detailed statistical analysis of their fine structure.

Contribution

The authors demonstrate a novel imaging technique combining slit-confocal microscopy with a solid immersion lens to analyze excitons in quantum dots at sub-wavelength resolution.

Findings

Achieved 400 nm spatial resolution in quantum dot emission mapping.

Found exchange splitting distribution centered at zero with 0.34 meV std.

Measured average exciton g factor of 3.1 at 3T magnetic field.

Abstract

We demonstrate sub-wavelength imaging of excitons confined to single CdTe quantum dots. By combining slit-confocal microscopy with a hemispherical solid immersion lens we simultaneously map the emission of thousands of single quantum dots with a spatial resolution of 400 nm. By analyzing the linear polarization of the quantum dot emissions at B=0T, we find that the distribution of the exchange splitting is centered at zero with a standard deviation of 0.34 meV. Similar experiments performed at B=3T give an average value of the exciton effective g factor of 3.1. This experimental approach provides an effective means to gain statistical information about the quantum dot exciton fine structure in the ensemble.