Near-unity coupling efficiency of a quantum emitter to a photonic crystal waveguide

Area of Science:

• Quantum optics and photonics
• Solid-state physics
• Nanotechnology

Background:

• Efficient coupling of quantum emitters to nanophotonic waveguides is crucial for quantum technologies.
• The β factor quantifies the probability of a single photon coupling into a desired waveguide mode.
• High β factors are essential for realizing single-photon transistors, quantum logic gates, and deterministic single-photon sources.

Purpose of the Study:

• To experimentally achieve a high β factor for a quantum dot coupled to a photonic crystal waveguide.
• To demonstrate a nearly ideal photon-matter interface for on-chip quantum applications.
• To assess the robustness of the β factor against variations in quantum dot properties.

Main Methods:

• Fabrication of a quantum dot-photonic crystal waveguide system.
• Experimental measurement of the β factor using optical spectroscopy.
• Characterization of single-emitter cooperativity (η).

Main Results:

• Achieved a β factor of 98.43% ± 0.04%, indicating highly efficient photon channeling.
• Obtained a single-emitter cooperativity (η) of 62.7 ± 1.5.
• Demonstrated that the β factor is robust to variations in quantum dot position and emission wavelength.

Conclusions:

• The quantum dot-photonic crystal waveguide system provides a near-ideal 1D artificial atom for photon-matter interaction.
• Photonic crystal waveguides are highly effective for efficient single-photon generation.
• The demonstrated system holds significant potential for on-chip photon-photon interactions and advanced quantum computing.