Diamond photonics for spin-based quantum information processing and sensing
With its long-lived electronic spin coherence and optical addressability, the nitrogen-vacancy (NV) center in diamond has attracted much interest as a potential solid-state qubit for quantum information applications. As with many such systems, a difficult challenge with the NV center is how to connect many together, as needed for large-scale computation. One possible route, which our group has pursued at HP Labs for several years, uses photonic networks combined with schemes based on optical interference and measurement to create long-distance entanglement. Two of the many requirements for this approach to succeed are control over the NV center’s energy level structure, and the ability to place NV centers into optical structures such as microcavities to enable efficient coupling to an optical channel.
This talk will mainly describe our work on coupling NV centers to optical microcavities and waveguides using various geometries, including structures made entirely from diamond, as well as hybrid structures. We have measured Purcell enhancement of the zero-phonon emission rate by factors estimated to be as high as 70, such that the zero-phonon fraction of the spontaneous emission increases from 3% to 70%. Spectral stability of the optical transitions remains a challenge in these structures. This can hopefully be addressed through a combination of materials improvements and dynamic Stark-shift tuning. Our group has also performed several recent experiments related to diamond-based magnetometry, which will be presented.
Dr. Charles Santori is a research staff member in the Large-Scale Integrated Photonics group at HP Labs. His research topics have included devices for quantum information processing in diamond, as well as devices for classical photonic interconnects and sensing. Prior to joining HP, Dr. Santori completed his graduate studies and post-doctoral research in the Yamamoto group at Stanford University, where he performed quantum-optical experiments involving InAs quantum dots and other atom-like systems in semiconductors.