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Chromium single photon emitters in diamond fabricated by ion implantation  [PDF]
Igor Aharonovich,Stefania Castelletto,Brett C. Johnson,Jeffrey C. McCallum,David A. Simpson,Andrew D. Greentree,Steven Prawer
Physics , 2010, DOI: 10.1103/PhysRevB.81.121201
Abstract: Controlled fabrication and identification of bright single photon emitters is at the heart of quantum optics and materials science. Here we demonstrate a controlled engineering of a chromium bright single photon source in bulk diamond by ion implantation. The Cr center has fully polarized emission with a ZPL centered at 749 nm, FWHM of 4 nm, an extremely short lifetime of ~1 ns, and a count rate of 500 kcounts/s. By combining the polarization measurements and the vibronic spectra, a model of the center has been proposed consisting of one interstitial chromium atom with a transition dipole along one of the <100> directions.
Imaging and quantum efficiency measurement of chromium emitters in diamond  [PDF]
I. Aharonovich,S. Castelletto,B. C. Gibson,B. C. Johnson,S. Prawer
Physics , 2010,
Abstract: We present direct imaging of the emission pattern of individual chromium-based single photon emitters in diamond and measure their quantum efficiency. By imaging the excited state transition dipole intensity distribution in the back focal plane of high numerical aperture objective, we determined that the emission dipole is oriented nearly orthogonal to the diamond-air interface. Employing ion implantation techniques, the emitters were engineered with various proximities from the diamond-air interface. By comparing the decay rates from the single chromium emitters at different depths in the diamond crystal, an average quantum efficiency of 28% was measured.
Photophysics of novel diamond based single photon emitters  [PDF]
I. Aharonovich,S. Castelletto,D. A. Simpson,A. D. Greentree,S. Prawer
Physics , 2009, DOI: 10.1103/PhysRevA.81.043813
Abstract: A detailed study of the photophysical properties of several novel color centers in chemical vapor deposition diamond is presented. These emitters show narrow luminescence lines in the near infra-red. Single photon emission was verified with continuous and pulsed excitation with emission rates at saturation in the MHz regime, whilst direct lifetime measurements reveal excited state lifetimes ranging from 1-14 ns. In addition, a number of quantum emitters demonstrate two level behavior with no bunching present in the second order correlation function. An improved method of evaluating the quantum efficiency through the direct measurement of the collection efficiency from two level emitters is presented and discussed. \
Engineering near infrared single photon emitters in ultrapure silicon carbide  [PDF]
F. Fuchs,B. Stender,M. Trupke,J. Pflaum,V. Dyakonov,G. V. Astakhov
Physics , 2014, DOI: 10.1038/ncomms8578
Abstract: Quantum emitters hosted in crystalline lattices are highly attractive candidates for quantum information processing, secure networks and nanosensing. For many of these applications it is necessary to have control over single emitters with long spin coherence times. Such single quantum systems have been realized using quantum dots, colour centres in diamond, dopants in nanostructures and molecules . More recently, ensemble emitters with spin dephasing times on the order of microseconds and room-temperature optically detectable magnetic resonance have been identified in silicon carbide (SiC), a compound being highly compatible to up-to-date semiconductor device technology. So far however, the engineering of such spin centres in SiC on single-emitter level has remained elusive. Here, we demonstrate the control of spin centre density in ultrapure SiC over 8 orders of magnitude, from below $10^{9}$ to above $10^{16} \,$cm$^{-3}$ using neutron irradiation. For a low irradiation dose, a fully photostable, room-temperature, near infrared (NIR) single photon emitter can clearly be isolated, demonstrating no bleaching even after $10^{14}$ excitation cycles. Based on their spectroscopic fingerprints, these centres are identified as silicon vacancies, which can potentially be used as qubits, spin sensors and maser amplifiers.
Study of narrowband single photon emitters in polycrystalline diamond films  [PDF]
Russell G. Sandstrom,Olga Shimoni,Aiden A. Martin,Igor Aharonovich
Physics , 2014, DOI: 10.1063/1.4901083
Abstract: Quantum information processing and integrated nanophotonics require robust generation of single photon emitters on demand. In this work we demonstrate that diamond films grown by microwave plasma chemical vapour deposition on a silicon substrate host bright, narrowband single photon emitters in the visible to near infrared spectral range. The emitters possess fast lifetime, absolute photostability, and exhibit full polarization at excitation and emission. Pulsed and continuous laser excitations confirm their quantum behaviour at room temperature, while low temperature spectroscopy is done to investigate their inhomogeneous broadening. Our results advance the knowledge of solid state single photon sources and open pathways for their practical implementation in quantum communication and quantum information processing.
Wide range electrical tunability of single photon emission from chromium-based colour centres in diamond  [PDF]
T. Müller,I. Aharonovich,L. Lombez,Y. Alaverdyan,A. N. Vamivakas,S. Castelletto,F. Jelezko,J. Wrachtrup,S. Prawer,M. Atatüre
Physics , 2011, DOI: 10.1088/1367-2630/13/7/075001
Abstract: We demonstrate electrical control of the single photon emission spectrum from chromium-based colour centres implanted in monolithic diamond. Under an external electric field the tunability range is typically three orders of magnitude larger than the radiative linewidth and at least one order of magnitude larger than the observed linewidth. The electric and magnetic field dependence of luminescence gives indications on the inherent symmetry and we propose Cr-X or X-Cr-Y type noncentrosymmetric atomic configurations as most probable candidates for these centres.
Single photon emitters based on Ni/Si related defects in single crystalline diamond  [PDF]
David Steinmetz,Elke Neu,Jan Meijer,Wolfgang Bolse,Christoph Becher
Physics , 2010, DOI: 10.1007/s00340-011-4402-x
Abstract: We present investigations on single Ni/Si related color centers produced via ion implantation into single crystalline type IIa CVD diamond. Testing different ion dose combinations we show that there is an upper limit for both the Ni and the Si dose 10^12/cm^2 and 10^10/cm^2 resp.) due to creation of excess fluorescent background. We demonstrate creation of Ni/Si related centers showing emission in the spectral range between 767nm and 775nm and narrow line-widths of 2nm FWHM at room temperature. Measurements of the intensity auto-correlation functions prove single-photon emission. The investigated color centers can be coarsely divided into two groups: Drawing from photon statistics and the degree of polarization in excitation and emission we find that some color centers behave as two-level, single-dipole systems whereas other centers exhibit three levels and contributions from two orthogonal dipoles. In addition, some color centers feature stable and bright emission with saturation count rates up to 78kcounts/s whereas others show fluctuating count rates and three-level blinking.
Spontaneous emission and collection efficiency enhancement of single emitters in diamond via plasmonic cavities and gratings  [PDF]
Jennifer T. Choy,Irfan Bulu,Birgit J. M. Hausmann,Erika Janitz,I-Chun Huang,Marko Lon?ar
Physics , 2013, DOI: 10.1063/1.4817397
Abstract: We demonstrate an approach, based on plasmonic apertures and gratings, to enhance the radiative decay rate of single NV centers in diamond, while simultaneously improving their collection efficiency. Our structures are based on metallic resonators formed by surrounding sub-wavelength diamond nanoposts with a silver film, which can enhance the spontaneous emission rate of an embedded NV center. However, the collection efficiency of emitted photons remains low due to losses to surface plasmons and reflections at the diamond-air interface. In this work, we mitigate photon losses into these channels by incorporating grating structures into the plasmonic cavity system.
Integrated Diamond Optics for Single Photon Detection  [PDF]
P. Siyushev,F. Kaiser,V. Jacques,I. Gerhardt,S. Bischof,H. Fedder,J. Dodson,M. Markham,D. Twitchen,F. Jelezko,J. Wrachtrup
Physics , 2010, DOI: 10.1063/1.3519849
Abstract: Optical detection of single defect centers in the solid state is a key element of novel quantum technologies. This includes the generation of single photons and quantum information processing. Unfortunately the brightness of such atomic emitters is limited. Therefore we experimentally demonstrate a novel and simple approach that uses off-the-shelf optical elements. The key component is a solid immersion lens made of diamond, the host material for single color centers. We improve the excitation and detection of single emitters by one order of magnitude, as predicted by theory.
Multiple intrinsically identical single photon emitters in the solid-state  [PDF]
Lachlan J. Rogers,Kay D. Jahnke,T. Teraji,Luca Marseglia,Christoph. Müller,Boris Naydenov,Hardy Schauffert,C. Kranz,Junichi Isoya,Liam P. McGuinness,Fedor Jelezko
Physics , 2013, DOI: 10.1038/ncomms5739
Abstract: Emitters of indistinguishable single photons are crucial for the growing field of quantum technologies. To realize scalability and increase the complexity of quantum optics technologies, multiple independent yet identical single photon emitters are also required. However typical solid-state single photon sources are inherently dissimilar, necessitating the use of electrical feedback or optical cavities to improve spectral overlap between distinct emitters. Here, we demonstrate bright silicon-vacancy (SiV-) centres in low-strain bulk diamond which intrinsically show spectral overlap of up to 91% and near transform-limited excitation linewidths. Our results have impact upon the application of single photon sources for quantum optics and cryptography, and the production of next generation fluorophores for bio-imaging.
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