Deterministic and highly indistinguishable single photons in the telecom C-band

Area of Science:

• Quantum optics
• Solid-state physics
• Nanotechnology

Background:

• Quantum dots are key for single-photon sources.
• High photon indistinguishability at telecom wavelengths is a challenge.
• Existing sources struggle with practical quantum communication needs.

Purpose of the Study:

• Develop a quantum dot single-photon source in the telecom C-band.
• Achieve high photon indistinguishability for quantum networks.
• Benchmark source performance and explore optimization strategies.

Main Methods:

• Fabricated an indium arsenide (InAs) quantum dot in InAlGaAs.
• Integrated the quantum dot into a circular Bragg grating resonator.
• Utilized multiple optical excitation schemes for optimization.

Main Results:

• Demonstrated a quantum dot single-photon source in the telecom C-band.
• Achieved a record raw two-photon interference visibility of (91.7 ± 0.2)%.
• Exceeded 90% visibility, a critical threshold for quantum applications.

Conclusions:

• The developed quantum dot source sets a new benchmark for indistinguishability in the C-band.
• This work significantly advances solid-state single-photon sources for quantum communication.
• The results pave the way for practical quantum networks utilizing telecom wavelengths.