- The paper demonstrates two-photon quantum interference from separate NV centers with a 66% contrast achieved by tuning dissimilar emissions into resonance.
- It employs the dc Stark effect and precise polarization control to isolate single transitions within the zero-phonon line.
- The findings highlight the potential for NV centers to enable remote entanglement and scalable quantum network applications.
Analysis of Two-Photon Quantum Interference from Separate Nitrogen Vacancy Centers in Diamond
The paper presents an investigation into the quantum interference of emissions from separate nitrogen vacancy (NV) centers in diamond, emphasizing the potential of such systems for quantum networking. NV centers are recognized as promising candidates for quantum information systems due to their stable photon emission properties and spin coherence capabilities. This paper capitalizes on these properties by demonstrating two-photon quantum interference (TPQI) from separate NV centers.
Key Findings
The main contribution of the paper is the observed TPQI with a contrast of 66%. This interference was achieved by isolating single transitions within the zero-phonon line (ZPL) and applying the dc Stark effect to tune dissimilar NV centers into resonance. The strategic use of optical filtering and polarization control enabled the isolation of the desired emission line, facilitating high-contrast interference.
Key numerical results include:
- Time-resolved two-photon interference contrast of 66% for parallel polarization, which is notably high for separate solid-state emitters.
- Tuning precision via the dc Stark effect allowed previously dissimilar NV center emissions to resonate, demonstrating the feasibility of controlling NV centers for practical quantum applications.
Implications
The observations affirm the potential for NV centers in building scalable quantum networks. This is particularly significant for implementing remote entanglement protocols and quantum communication. The use of NV centers allows for integrating robust, long-lived electronic spins with coherent properties into a network, enabling the possibility of combined spin-photon quantum systems.
Future Directions
The paper highlights certain practical challenges, such as broadening resulting from photon emission from neutral charge states and spin polarization imperfections, which can affect visibility. Future endeavors could benefit from resonant excitation techniques to mitigate these complications, further refining photonic indistinguishability. Enhancements such as embedding NV centers into optical cavities could significantly boost the photon collection efficiency and interaction rates.
Furthermore, the ability to exploit electric field tuning opens new avenues for dynamically controlling and entangling multiple NV centers, critical for larger quantum network implementations. The engagement with resonant conditions at both the atomic and spin level implies promising possibilities for extending entanglement operations beyond laboratory conditions to more complex network structures.
Encompassing both theoretical predictions and experimental achievements, this research delineates progress in the field of solid-state quantum networks, pinpointing a versatile pathway for future quantum information processing endeavors.