A nanodiamond-tapered fiber system with high single-mode coupling efficiency

Area of Science:

• Quantum Optics
• Nanophotonics
• Materials Science

Background:

• Nitrogen-vacancy (NV) defect centers in diamond are promising solid-state sources of single photons.
• Efficiently coupling single photons from nanodiamonds into optical fibers is crucial for quantum applications.
• Existing methods face challenges in achieving high collection efficiencies and integration with photonic circuits.

Purpose of the Study:

• To develop a highly efficient fiber-coupled single photon source based on nanodiamonds.
• To demonstrate high single-photon generation rates within a single-mode fiber.
• To enable integration with other nanophotonic structures for advanced quantum experiments.

Main Methods:

• Fabrication of single nanodiamonds with nitrogen-vacancy (NV) defect centers.
• Deposition of nanodiamonds onto a tapered optical fiber with a 273 nm diameter.
• Characterization of single-photon emission rates and coupling efficiency into the fiber.
• Demonstration of cryogenic cooling and evanescent coupling capabilities.

Main Results:

• Achieved a record-high single-photon generation rate of 689,000 photons per second from a single NV center.
• Successfully coupled single photons into a single-mode optical fiber with high efficiency.
• Demonstrated the system's compatibility with cryogenic temperatures and evanescent coupling to nanophotonic structures.

Conclusions:

• The developed fiber-coupled diamond-based single photon system offers unprecedented efficiency for quantum light generation.
• This platform is highly suitable for integrated quantum transmission, quantum interference, quantum random number generation, and nano-magnetometry.
• The system represents a significant advancement towards practical, on-chip quantum information processing and sensing.