Tuning exciton and biexciton transition energies and fine structure splitting through hydrostatic pressure in single InGaAs quantum dots

TL;DR

This study demonstrates the in situ tuning of exciton and biexciton energies, as well as fine structure splitting, in single InGaAs quantum dots using hydrostatic pressure, enabling control over photon emission properties for quantum information applications.

Contribution

The paper introduces a method to tune quantum dot emission energies and fine structure splitting via hydrostatic pressure, supported by atomistic calculations, advancing quantum photonics control.

Findings

Achieved up to 380 meV exciton energy shift

Controlled fine structure splitting up to 180 μeV

Produced biexciton antibinding-binding transition

Abstract

We demonstrate that the exciton and biexciton emission energies as well as exciton fine structure splitting (FSS) in single (In,Ga)As/GaAs quantum dots (QDs) can be efficiently tuned using hydrostatic pressure in situ in an optical cryostat at up to 4.4 GPa. The maximum exciton emission energy shift was up to 380 meV, and the FSS was up to 180 $\mu$eV. We successfully produced a biexciton antibinding-binding transition in QDs, which is the key experimental condition that generates color- and polarization-indistinguishable photon pairs from the cascade of biexciton emissions and that generates entangled photons via a time-reordering scheme. We perform atomistic pseudopotential calculations on realistic (In,Ga)As/GaAs QDs to understand the physical mechanism underlying the hydrostatic pressure-induced effects.