Eine Nieheimer Flechthecke

Zu den landschaftstypischen Kulturelementen aus Westfalen, die volkskundliches Interesse verdienen, gehört auch die Nieheimer Flechthecke. Die Bezeichnung deutet schon die lokale Verbreitung dieser Hecken an. Es ist eine Art der Weideabgrenzung, die besonders im Raum Nieheim, der Nordwestecke des Oberwälder Landes, verbreitet war und sich dort noch relativ lange gehalten hat. Hecken waren hier das prägende Landschaftbild und stehen im engen Zusammenhang mit der Weidewirtschaft. Flechthecken gibt es auch in anderen Gegenden Westfalens, jedoch unterscheiden sie sich vom Nieheimer Typ

Deep levels in homoepitaxial boron-doped diamond films studied by capacitance transient spectroscopies

International audienceDeep level transient spectroscopies (DLTS) applied to Schottky junctions made on homoepitaxial boron-doped diamond films show the existence of two traps. A deep acceptor, negatively charged and strongly attractive for holes, 1.57 eV above the valence band edge displays the characteristic features of a complex defect due to interacting centers and impurities, also displaying some evolutions after thermal cycles, possibly due to hydrogen effusion or diffusion. It is tentatively ascribed to association of a boron atom, a vacancy and several hydrogen atoms. A deep donor, 1.13 eV above the valence band edge, able to compensate the boron acceptors, is attributed to a defect correlated with dislocations. It could be due to the positively charged carbon vacancy. These conclusions are drawn from the Fourier transform-DLTS results coupled with isothermal time domain algorithms allowing the discrimination of multiple emission rates with high resolution

Optical signatures of silicon-vacancy spins in diamond

Colour centres in diamond have emerged as versatile tools for solid-state quantum technologies ranging from quantum information to metrology, where the nitrogen-vacancy centre is the most studied to date. Recently, this toolbox has expanded to include novel colour centres to realize more efficient spin-photon quantum interfaces. Of these, the silicon-vacancy centre stands out with highly desirable photonic properties. The challenge for utilizing this centre is to realize the hitherto elusive optical access to its electronic spin. Here we report spin-tagged resonance fluorescence from the negatively charged silicon-vacancy centre. Our measurements reveal a spin-state purity approaching unity in the excited state, highlighting the potential of the centre as an efficient spin-photon quantum interface

Single photon emitters based on Ni/Si related defects in single crystalline diamond

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.Comment: 7 pages, submitted to Applied Physics B, revised versio

Coupling of silicon-vacancy centers to a single crystal diamond cavity

Optical coupling of an ensemble of silicon-vacancy (SiV) centers to single-crystal diamond microdisk cavities is demonstrated. The cavities are fabricated from a single-crystal diamond membrane generated by ion implantation and, electrochemical liftoff followed by homo-epitaxial overgrowth. Whispering gallery modes which spectrally overlap with the zero-phonon line (ZPL) of the SiV centers and exhibit quality factors ~2200 are measured. Lifetime reduction from 1.8 ns to 1.48 ns is observed from SiV centers in the cavity compared to those in the membrane outside the cavity. These results are pivotal in developing diamond integrated photonics networks