Magneto-optical spectroscopy of single charge-tunable InAs/GaAs quantum dots emitting at telecom wavelengths

TL;DR

This study provides a comprehensive optical characterization of single InAs/GaAs quantum dots emitting at telecom wavelengths, revealing their physical properties and tunability under external fields, crucial for quantum technology applications.

Contribution

It presents the first detailed spectroscopic analysis of charge-tunable telecom-wavelength quantum dots, including wavefunction properties and magnetic/electric field effects.

Findings

Strong confinement regime confirmed for carriers.

Electric field tunability up to 7 meV demonstrated.

Magnetic field rotation causes significant diamagnetic coefficient reduction.

Abstract

We report on the optical properties of single InAs/GaAs quantum dots emitting near the telecommunication O-band, probed via Coulomb blockade and non-resonant photoluminescence spectroscopy, in the presence of external electric and magnetic fields. We extract the physical properties of the electron and hole wavefunctions, including the confinement energies, interaction energies, wavefunction lengths, and $g$-factors. For excitons, we measure the permanent dipole moment, polarizability, diamagnetic coefficient, and Zeeman splitting. The carriers are determined to be in the strong confinement regime. Large range electric field tunability, up to 7 meV, is demonstrated for excitons. We observe a large reduction, up to one order of magnitude, in the diamagnetic coefficient when rotating the magnetic field from Faraday to Voigt geometry due to the unique dot morphology. The complete spectroscopic characterization of the fundamental properties of long-wavelength dot-in-a-well structures provides insight for the applicability of quantum technologies based on quantum dots emitting at telecom wavelengths.