The development of solid-state photonic quantum technologies is of great interest for fundamental studies of light-matter interactions and quantum information science. Diamond has turned out to be an attractive material for integrated quantum information processing due to the extraordinary properties of its colour centres enabling e.g. bright single photon emission and spin quantum bits. To control emitted photons and to interconnect distant quantum bits, micro-cavities directly fabricated in the diamond material are desired. However, the production of photonic devices in high-quality diamond has been a challenge so far. Here we present a method to fabricate one-and two-dimensional photonic crystal micro-cavities in single-crystal diamond, yielding quality factors up to 700. Using a post-processing etching technique, we tune the cavity modes into resonance with the zero phonon line of an ensemble of silicon-vacancy centres and measure an intensity enhancement by a factor of 2.8. The controlled coupling to small mode volume photonic crystal cavities paves the way to larger scale photonic quantum devices based on single-crystal diamond.A number of seminal experiments have demonstrated the prospects of colour centres in diamond, in particular the negatively charged nitrogen-vacancy centre

Deterministic coupling of single solid-state emitters to nanocavities is the key for integrated quantum information devices. We here fabricate a photonic crystal cavity around a preselected single silicon-vacancy color center in diamond and demonstrate modification of the emitters internal population dynamics and radiative quantum efficiency. The controlled, room-temperature cavity coupling gives rise to a resonant Purcell enhancement of the zero-phonon transition by a factor of 19, coming along with a 2.5-fold reduction of the emitter's lifetime.

We present the controlled creation of single nitrogen-vacancy (NV) centers via ion implantation at the center of a photonic crystal cavity which is fabricated in an ultrapure, single crystal diamond membrane. Highresolution placement of NV centers is achieved using collimation of a 5 keV-nitrogen ion beam through a pierced tip of an atomic force microscope (AFM). We demonstrate coupling of the implanted NV centers' broad band fluorescence to a cavity mode and observe Purcell enhancement of the spontaneous emission. The results are in good agreement with a master equation model for the cavity coupling.The nitrogen-vacancy (NV) center 1 in diamond has been successfully implemented as solid state quantum bit that meets all essential requirements for quantum information processing such as optical initialization, control and readout of the spin state. The challenge remains to extend the quantum system from a small number of qubits to large scale networks. Seminal experiments already demonstrated remote entanglement between individual NV centers via two-photon quantum interference 2,3 . The hitherto poor rate of entanglement events 2,3 could be strongly increased by coupling the NV centers to optical microcavities. The effects range from enhancement and spectral reshaping of the NV spectrum over cavity-enhanced spin state readout 4 to cavity mediated entanglement between two NV centers 5 . Photonic crystal (PhC) cavities directly fabricated in diamond are ideal for color center-cavity coupling experiments as they exhibit high Q-factors and extremely small mode volumes. For solid state systems, it is however challenging to precisely place the emitter in the maximum of the cavity electric field to achieve optimum coupling.Past experiments that demonstrated coupling of single NV centers to PhC cavities 6,7 have largely relied on random positioning. Controlled lateral positioning and emitter-cavity coupling has recently been achieved via a tailored fabrication process of a PhC around a single silicon-vacancy center in diamond 8 . Here, we pursuit the complementary approach based on targeted implantation of NV centers into pre-defined cavities in diamond. In recent years, several techniques for spatially selective formation of single NV centers in bulk diamond have been developed involving focused nitrogen ion beam 9 , implantation through pierced AFM-tips 10,11 and through small apertures in e-beam resist 12,13 , mica foils 14 , and silicon masks 15 . Using the silicon mask simultaneously as a) Di am on d (a) (b) 500nm (c) (d) 640 660 680 c3 c2 Intensity (a.u.) Wavelength λ (nm) c1 500nm NV ZPL FIG. 1. Nanoimplantation process of nitrogen ions into diamond-based photonic crystal cavities: (a) Schematic diagram of the nanoimplanter setup that combines collimation and positioning of a 5 keV nitrogen ion beam with an AFM. A small hole in the AFM tip serves as an aperture for the ion beam. (b) SEM image and (c) AFM image of a fabricated M1-cavity. (d) M1-cavity spectrum prior implantation reveals three cavity modes c1, c2 and ...

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Articles you may be interested inCreation of quantum entanglement with two separate diamond nitrogen vacancy centers coupled to a photonic molecule

Surface patterning in the micro- and nanometer-range by means of pulsed laser interference has repeatedly proven to be a versatile tool for surface functionalization. With these techniques, however, the surface is often changed not only in terms of morphology but also in terms of surface chemistry. In this study, we present an in-depth investigation of the chemical surface modification occurring during surface patterning of copper by ultrashort pulsed direct laser interference patterning (USP-DLIP). A multimethod approach of parallel analysis using visualizing, topography-sensitive, and spectroscopic techniques allowed a detailed quantification of surface morphology as well as composition and distribution of surface chemistry related to both processing and atmospheric aging. The investigations revealed a heterogeneous surface composition separated in peak and valley regions predominantly consisting of Cu2O, as well as superficial agglomerations of CuO and carbon species. The evaluation was supported by a modeling approach for the quantification of XPS results in relation to heterogeneous surface composition, which was observed by means of a combination of different spectroscopic techniques. The overall results provide a detailed understanding of the chemical and topographical surface modification during USP-DLIP, which allows a more targeted use of this technology for surface functionalization.

A new method for the image acquisition in scanning electron microscopy (SEM) was introduced. The method used adaptively increased pixel-dwell times to improve the signal-to-noise ratio (SNR) in areas of high detail. In areas of low detail, the electron dose was reduced on a per pixel basis, and a-posteriori image processing techniques were applied to remove the resulting noise. The technique was realized by scanning the sample twice. The first, quick scan used small pixel-dwell times to generate a first, noisy image using a low electron dose. This image was analyzed automatically, and a software algorithm generated a sparse pattern of regions of the image that require additional sampling. A second scan generated a sparse image of only these regions, but using a highly increased electron dose. By applying a selective low-pass filter and combining both datasets, a single image was generated. The resulting image exhibited a factor of ≈3 better SNR than an image acquired with uniform sampling on a Cartesian grid and the same total acquisition time. This result implies that the required electron dose (or acquisition time) for the adaptive scanning method is a factor of ten lower than for uniform scanning.

Hard and wear resistant coatings are widely used as tribological layers to protect tools from wear, oxidation and corrosion. Characterizing the deformation behavior of coatings is essential for understanding wear mechanisms and to design multi-layered coatings that withstand severe working conditions. Micro-mechanical properties of Ti(C,N) and Zr(C,N) coatings deposited by chemical vapor deposition on a WC-Co cemented carbide substrate were examined by micro-compression testing using a nanoindenter equipped with a flat punch. Scanning Electron Microscopy, Focused Ion Beam, Electron Backscattered Diffraction and Finite Element Modeling were combined to analyze the deformation mechanisms of the carbonitride layers at room temperature. The results revealed that Ti(C,N) undergoes