Metamaterials and metasurfaces can be seen as a novel approach for constructing practical quantum photonic systems. In this talk, we present our recent advances in controlling single-photon emission from nitrogen-vacancy (NV) color centers in nanodiamonds using CMOS-compatible hyperbolic metamaterials. Further, we discuss how an increased photonic density of states affects the optical readout of the NV center spin-state. These results can be useful for engineering on-chip room-temperature quantum registers.
Integration of solid-state quantum emitters such as NV center in diamond with tapered optical fiber is demanded by number of applications ranging from sensing and imaging to quantum communications and computations. Nevertheless, utilization of a single NV center coupled with an optical fiber meets significant challenge of fiber fluorescence that can considerably mask emission of the quantum object. In this paper, we analyze main sources of such fluorescence for the case of NV center coupled to tapered single mode optical fiber and discuss possible ways of improving signal to noise ratio in this case.
NV center in diamond is attracting a lot of attention in quantum information processing community . Been spin system in clean and well-controlled environment of diamond it shows outstanding performance as quantum memory even at room temperature, spin control with single shot optical readout and possibility to build up quantum registers even on single NV center. Moreover, NV centers could be used as high-resolution sensitive elements of detectors of magnetic or electric field, temperature, tension, force or rotation. For all of these applications collection of the light emitted by NV center is crucial point. There were number of approaches suggested to address this issue, proposing use of surface plasmoms , manufacturing structures in diamond  etc. One of the key feature of any practically important interface is compatibility with the fiber technology. Several groups attacking this problem using various approaches. One of them is placing of nanodiamonds in the holes of photonic crystal fiber , another is utilization of AFM to pick and place nanodiamond on the tapered fiber. We have developed a novel technique of placing a nanodiamond with single NV center on the tapered fiber by controlled transfer of a nanodiamond from one “donor” tapered fiber to the “target” clean tapered fiber. We verify our ability to transfer only single color centers by means of measurement of second order correlation function. With this technique, we were able to double collection efficiency of confocal microscope. The majority of the factors limiting the collection of photons via optical fiber are technical and may be removed allowing order of magnitude improved in collection. We also discuss number of extensions of this technique to all fiber excitation and integration with nanostructures. References:  Marcus W. Doherty, Neil B. Manson, Paul Delaney, Fedor Jelezko, Jörg Wrachtrup, Lloyd C.L. Hollenberg , " The nitrogen-vacancy colour centre in diamond," Physics Reports, vol. 528, no. 1, p. 1–45, 2013.  A.V. Akimov, A. Mukherjee, C.L. Yu, D.E. Chang, A.S. Zibrov, P.R. Hemmer, H. Park and M.D. Lukin, "Generation of single optical plasmons in metallic nanowires coupled to quantum dots," Nature, vol. 450, p. 402–406, 2007.  Michael J. Burek , Yiwen Chu, Madelaine S.Z. Liddy, Parth Patel, Jake Rochman , Srujan Meesala, Wooyoung Hong, Qimin Quan, Mikhail D. Lukin and Marko Loncar High quality-factor optical nanocavities in bulk single-crystal diamond, Nature communications 6718 (2014)  Tim Schroder, Andreas W. Schell, Gunter Kewes, Thomas Aichele, and Oliver Benson Fiber-Integrated Diamond-Based Single Photon Source, Nano Lett. 2011, 11, 198-202 Lars Liebermeister, et. al. “Tapered fiber coupling of single photons emitted by a deterministically positioned single nitrogen vacancy center”, Appl. Phys. Lett. 104, 031101 (2014)