High-Q cavity interface for color centers in thin film diamond

Area of Science:

• Quantum Information Science
• Materials Science
• Nanotechnology

Background:

• Quantum information technology promises advanced computation and secure communication through entanglement distribution.
• Diamond-based quantum memory nodes are crucial for extending quantum networks.
• Photonic crystal (PhC) cavities are essential for efficient spin-photon interfaces in quantum systems.

Purpose of the Study:

• To demonstrate high-quality one- and two-dimensional PhC cavities in thin-film diamond.
• To develop a simple, high-yield fabrication process for these cavities.
• To achieve efficient fiber coupling and demonstrate optical coupling with a single silicon-vacancy (SiV) center.

Main Methods:

• Fabrication of 1D and 2D PhC cavities in thin-film diamond using conventional planar techniques.
• Characterization of cavity quality factors (Q).
• Demonstration of fiber coupling and optical coupling with a single SiV center at 4K.

Main Results:

• Achieved record-high quality factors (Q) of 1.8 × 10^5 for 1D and 1.6 × 10^5 for 2D visible PhC cavities.
• Developed a simple and high-yield fabrication process, avoiding complex undercut methods.
• Demonstrated high photon extraction efficiency in fiber-coupled 1D cavities.
• Achieved a Purcell factor of 18 for optical coupling between a single SiV center and a 1D cavity.

Conclusions:

• The demonstrated diamond PhC cavities represent a significant advancement for quantum information processing.
• The high-Q cavities and efficient coupling pave the way for improved quantum memory nodes and scalable quantum networks.
• This fabrication approach offers a practical pathway for the development of robust quantum technologies.