High-Purity Single Photon Extraction from Diamond Nitrogen-Vacancy Centers in Low-Numerical-Aperture Optical Systems...

Area of Science:

• Quantum Optics
• Materials Science
• Nanotechnology

Background:

• Solid-state quantum emitters like nitrogen-vacancy (NV) centers are crucial for scalable quantum technologies.
• Challenges include random emitter distribution and broad emission, hindering efficient single-photon extraction, especially in low-numerical-aperture (NA) systems.
• Low-NA systems are vital for compact and scalable quantum photonic applications.

Purpose of the Study:

• To present a defect-selective metalens integration approach for precise and efficient single photon collection from individual NV centers.
• To overcome limitations of low-NA optical systems for quantum photonics.
• To enable high-purity single-photon generation and collection in scalable solid-state quantum systems.

Main Methods:

• Utilized an in situ transfer-printing process to deterministically stamp silicon dioxide metalenses onto selected NV centers.
• Integrated metalenses with NV centers located 25 µm below the diamond surface.
• Characterized the reshaped emission beam and measured photon collection efficiency and purity.

Main Results:

• Achieved a 40-fold enhancement in photon collection efficiency using a low-NA (0.07) objective lens.
• Demonstrated exclusive emission detection from metalens-coupled NV centers, filtering background noise.
• Confirmed high-purity single-photon generation with second-order correlation measurements yielding g⁽²⁾(0) = 0.04.

Conclusions:

• The defect-selective metalens integration is a scalable, site-specific approach addressing key limitations in low-NA quantum photonics.
• This method enables precise and efficient single-photon collection from solid-state quantum emitters.
• Paves the way for compact, fiber-integrated solid-state quantum photonic systems.