A. Young

University of Bristol, Bristol, ENG, United Kingdom

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Publications (4)7.83 Total impact

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    ABSTRACT: We use focused ion beam (FIB) etching to create suspended photonic crystal cavities in diamond. Our goal is to enhance and control the spontaneous emission of single N-V colour centres, which act like single `two-level atoms' emitting single photons. The single nitrogen-vacancy (N-V) colour centre in diamond has attracted a lot of interest because it can be optically addressed, is photostable at room temperature and has a paramagnetic ground state whose spin can be initialized and read-out optically. By enclosing the (N-V) colour centre in a resonant cavity we aim to develop rapid readout of this optically addressable single spin. We show a technique using FIB and confocal microscopy to locate single N-V centres and discuss progress towards etching cavities around single centres.
    Optical Communication (ECOC), 2010 36th European Conference and Exhibition on; 10/2010
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    ABSTRACT: A key step in the use of diamond nitrogen vacancy (NV) centers for quantum computational tasks is a single shot quantum non-demolition measurement of the electronic spin state. Here, we propose a high fidelity measurement of the ground state spin of a single NV center, using the effects of cavity quantum electrodynamics. The scheme we propose is based in the one-dimensional atom or Purcell regime, removing the need for high Q cavities that are challenging to fabricate. The ground state spin of the NV center has a splitting of ≈6–10 μeV, which can be resolved in a high-resolution absorption measurement. By incorporating the center in a low-Q and low volume cavity we show that it is possible to perform single shot readout of the ground state spin using a weak laser with an error rate of ≈7×10−3, when realistic experimental parameters are considered. Since very low levels of light are used to probe the state of the spin we limit the number of florescence cycles, which dramatically reduces the measurement induced decoherence approximating a non-demolition measurement of ground state spin.
    New Journal of Physics 01/2009; 11(1):013007. · 4.06 Impact Factor
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    ABSTRACT: We propose a high efficiency high fidelity measurement of the ground state spin of a single NV center in diamond, using the effects of cavity quantum electrodynamics. The scheme we propose is based in the one dimensional atom or Purcell regime, removing the need for high Q cavities that are challenging to fabricate. The ground state of the NV center consists of three spin levels $^{3}A_{(m=0)}$ and $^{3}A_{(m=\pm1)}$ (the $\pm1$ states are near degenerate in zero field). These two states can undergo transitions to the excited ($^{3}E$) state, with an energy difference of $\approx7-10$ $\mu$eV between the two. By choosing the correct Q factor, this small detuning between the two transitions results in a dramatic change in the intensity of reflected light. We show the change in reflected intensity can allow us to read out the ground state spin using a low intensity laser with an error rate of $\approx5.5\times10^{-3}$, when realistic cavity and experimental parameters are considered. Since very low levels of light are used to probe the state of the spin we limit the number of florescence cycles, thereby limiting the non spin preserving transitions through the intermediate singlet state $^{1}A$.
    08/2008;
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    ABSTRACT: We propose a quantum non-demolition method - giant Faraday rotation - to detect a single electron spin in a quantum dot inside a microcavity where negatively-charged exciton strongly couples to the cavity mode. Left- and right-circularly polarized light reflected from the cavity feels different phase shifts due to cavity quantum electrodynamics and the optical spin selection rule. This yields giant and tunable Faraday rotation which can be easily detected experimentally. Based on this spin-detection technique, a scalable scheme to create an arbitrary amount of entanglement between two or more remote spins via a single photon is proposed. Comment: 5 pages, 3 figures
    Physical review. B, Condensed matter 08/2007; · 3.77 Impact Factor