Quantum interference of identical photons from remote GaAs quantum dots

Area of Science:

• Quantum physics
• Quantum optics
• Semiconductor quantum dots

Background:

• Photonic quantum technology is crucial for quantum communication, simulation, and information processing.
• Scaling quantum applications requires indistinguishable single photons from multiple sources.
• A major challenge is the low quantum coherence between photons from independent quantum dots.

Purpose of the Study:

• To demonstrate high-visibility two-photon interference using photons from separate GaAs quantum dots.
• To overcome the roadblock of poor quantum coherence in current quantum dot technology.
• To establish GaAs quantum dots as a scalable platform for coherent single photon generation.

Main Methods:

• Utilizing semiconductor GaAs quantum dots as bright and fast single photon sources.
• Demonstrating two-photon interference by exploiting quantum interference of photons.
• Rejecting phonon sideband emission while retaining zero phonon line emission.
• Implementing a photonic controlled-not gate and generating entangled photons.

Main Results:

• Achieved near-unity two-photon interference visibility (93.0 ± 0.8%) between photons from separate quantum dots.
• Demonstrated a photonic controlled-not circuit.
• Generated entanglement between photons from different origins with a fidelity of (85.0 ± 1.0)%.
• High mutual coherence attributed to high-quality materials, diode structure, and quantum dot size.

Conclusions:

• GaAs quantum dots provide a viable and scalable platform for generating coherent single photons.
• The demonstrated high-visibility interference and entanglement fidelity pave the way for advanced quantum photonic devices.
• Overcoming coherence limitations is key to advancing quantum communication and computation.