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A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
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Bright nanoscale source of deterministic entangled photon pairs violating Bell's inequality
Klaus D Jöns1,2, Lucas Schweickert3,4, Marijn A M Versteegh3,4,5,6
1Applied Physics Department, Royal Institute of Technology, Albanova University Centre, Roslagstullsbacken 21, 106 91, Stockholm, Sweden. klausj@kth.se.
Scientific Reports
|May 12, 2017
Summary
Researchers developed a bright quantum light source using a nanowire waveguide and quantum dot to generate entangled photons. This breakthrough enhances secure quantum communication technologies like quantum key distribution.
Area of Science:
- Quantum Information Science
- Nanophotonics
- Solid-State Physics
Background:
- Efficient distribution of entangled photons is crucial for global, secure quantum communication channels.
- Photons are ideal quantum information carriers for long-distance, low-loss interconnects.
- A quantum light source with high qubit fidelity and on-demand bright emission remains a challenge.
Purpose of the Study:
- To demonstrate a bright photonic nanostructure for generating polarization-entangled photon pairs.
- To achieve strong violation of Bell's inequality using the generated entangled photons.
- To enhance entanglement fidelity for practical quantum communication applications.
Main Methods:
- Fabrication of a tapered nanowire waveguide encapsulating a highly symmetric InAsP quantum dot.
- Utilizing a quasi-resonant excitation scheme at the InP nanowire resonance.
- Performing Bell tests using the Clauser-Horne-Shimony-Holt (CHSH) inequality.
Main Results:
- Collection of approximately 200 kHz entangled photon pairs, a 20-fold enhancement over bare quantum dots.
- Clear violation of the CHSH inequality by up to 9.3 standard deviations.
- Enhanced entanglement fidelity (F = 0.817 ± 0.002) without temporal post-selection, leading to a 25 standard deviation violation in a different basis.
Conclusions:
- The developed nanowire-based quantum light source shows significant potential for secure data communication.
- Applications include measurement-device-independent quantum key distribution and quantum repeater protocols.
- This work advances the development of practical quantum communication technologies.
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