Highly indistinguishable photons from deterministic quantum-dot microlenses utilizing three-dimensional in situ...

Area of Science:

• Quantum optics
• Solid-state physics
• Nanotechnology

Background:

• Advanced quantum communication requires non-classical light sources.
• High flux rates and purity of single photons are essential.
• Existing quantum light sources face limitations in efficiency and purity.

Purpose of the Study:

• To develop a robust quantum device approach for high-quality single-photon emission.
• To deterministically fabricate microlenses with integrated single quantum dots.
• To enhance photon extraction efficiency and single-photon properties.

Main Methods:

• Deterministic fabrication of microlenses using in situ 3D electron-beam lithography.
• Precise alignment of microlenses to pre-selected single quantum dots.
• Utilizing cathodoluminescence spectroscopy at cryogenic temperatures.

Main Results:

• Achieved enhanced photon-extraction efficiency of (23±3)%.
• Demonstrated close to pure single-photon emission with high indistinguishability (up to (80±7)%).
• Preserved single-photon purity and indistinguishability at high excitation power.

Conclusions:

• Deterministic quantum-dot microlenses offer a flexible and robust solution for quantum communication.
• The fabricated devices significantly improve key parameters for single-photon sources.
• This approach paves the way for scalable and high-performance quantum devices.