Wavelength-tunable high-fidelity entangled photon sources enabled by dual Stark effects.

Area of Science:

• Quantum Information Science
• Solid-State Physics
• Optoelectronics

Background:

• Quantum internet requires quantum repeaters with multiple entangled photon sources of identical wavelengths.
• Semiconductor quantum dots offer deterministic entangled photon pair generation with high fidelity.
• Challenges include non-uniform emission wavelengths and fidelity reduction from exciton fine-structure splitting.

Purpose of the Study:

• To demonstrate wavelength-tunable entangled photon sources based on droplet-etched GaAs quantum dots.
• To overcome the independent tunability limitations of emission wavelength and fidelity.
• To enable scalable, on-demand entangled photon sources for quantum networks.

Main Methods:

• Utilized droplet-etched GaAs quantum dots.
• Employed a hybrid tuning scheme combining AC and quantum-confined Stark effects.
• Tuned emission wavelength while maintaining high entanglement fidelity.

Main Results:

• Achieved wavelength tunability of ~1 meV.
• Preserved entanglement fidelity exceeding 0.955(1) across the tuning range.
• Demonstrated multiple wavelength-matched sources with fidelity > 0.919(3).

Conclusions:

• The hybrid tuning scheme effectively addresses challenges in creating wavelength-matched quantum dot sources.
• This advancement paves the way for robust and scalable entangled photon sources.
• Enables progress towards practical quantum internet and integrated quantum optical circuits.