Laser writing of coherent colour centres in diamond

Optically active point defects in crystals have gained widespread attention as photonic systems that can find use in quantum information technologies [1,2]. However challenges remain in the placing of individual defects at desired locations, an essential element of device fabrication. Here we report the controlled generation of single nitrogen-vacancy (NV) centres in diamond using laser writing [3]. The use of aberration correction in the writing optics allows precise positioning of vacancies within the diamond crystal, and subsequent annealing produces single NV centres with up to 45% success probability, within about 200 nm of the desired position. Selected NV centres fabricated by this method display stable, coherent optical transitions at cryogenic temperatures, a pre-requisite for the creation of distributed quantum networks of solid-state qubits. The results illustrate the potential of laser writing as a new tool for defect engineering in quantum technologies

Laser writing of coherent colour centres in diamond

Optically active point defects in crystals have gained widespread attention as photonic systems that can find use in quantum information technologies. However challenges remain in the placing of individual defects at desired locations, an essential element of device fabrication. Here we report the controlled generation of single negatively charged nitrogen-vacancy (NV-) centres in diamond using laser writing. Aberration correction in the writing optics allows precise positioning of vacancies within the diamond crystal, and subsequent annealing produces single NV- centres with up to (45 ± 15)% success probability, within about 200 nm of the desired position in the transverse plane. Selected NV- centres display stable, coherent optical transitions at cryogenic temperatures, a pre-requisite for the creation of distributed quantum networks of solid-state qubits. The results illustrate the potential of laser writing as a new tool for defect engineering in quantum technologies, and extend laser processing to the single defect domain

Quantitative determination of the Mn site distribution in ultrathin Ga0.80Mn0.20As layers with high critical temperatures: A Rutherford backscattering channeling investigation

International audienceThe Mn dopant distribution in ultrathin (20 nm) highly doped (nominal x = 0.20) Ga1-x Mn-x As epitaxial films with critical temperatures close to 175 K and magnetization of 100 emu/cm(3) is analyzed by Rutherford backscattering spectrometry (RBS) in a random and channeling configuration. We could quantify the total concentration and the respective fraction of substitutional, interstitial, and random site Mn ions in as-grown and annealed samples. The measured total Mn concentration is x = 0.23. In the as-grown state 30% of the Mn dopant is located on interstitial sites. Thermal annealings at 180 degrees C for several hours monotonically reduce the interstitial Mn fraction to 11%. Simultaneously the fraction of randomly located Mn is increased by the same amount. The substitutional Mn concentration is stable under these annealing conditions. The effective Mn concentration could be increased to x = 0.13. However, the critical temperature does not increase proportionally with the magnetization. A comparison of the magnetization values demonstrates that the interstitial Mn ions are already incorporated during the growth in the form of Mn-Ga-Mn-i clusters

Coherent Manipulation with Resonant Excitation and Single Emitter Creation of Nitrogen Vacancy Centers in 4H Silicon Carbide.

Silicon carbide (SiC) has become a key player in the realization of scalable quantum technologies due to its ability to host optically addressable spin qubits and wafer-size samples. Here, we have demonstrated optically detected magnetic resonance (ODMR) with resonant excitation and clearly identified the ground state energy levels of the NV centers in 4H-SiC. Coherent manipulation of NV centers in SiC has been achieved with Rabi and Ramsey oscillations. Finally, we show the successful generation and characterization of single nitrogen vacancy (NV) center in SiC employing ion implantation. Our results highligh the key role of NV centers in SiC as a potential candidate for quantum information processing

Hydrogenated amorphous carbon film coating of PET bottles for gas diffusion barriers

16th European Conference on Diamond, Diamond-Like Materials, Carbon Nanotubes, and Nitrides, Toulouse, FRANCE, SEP 11-16, 2005International audienceThe addition of a gas-impermeable coating on the inside wall of a standard polyethylene tereplithalate (PET) bottle has long been considered as a way to improve the packaging for beer, juice and carbonated soft drinks. We have developed a plasma-assisted deposition process suitable for the deposition of 100 nm thick, transparent, hydrogenated amorphous carbon (a-C:H) films on PET surfaces. The Sidel plasma technology uses an acetylene gas precursor and a microwave plasma, which allows us to obtain a high deposition rate of 60 nm/s necessary for industrial process flows. The a-C:H films provide a 50-fold reduction of the permeation rates Of O-2 . The composition, optical, structural and defect properties of the a-C:H films were characterized by Rutherford Back Scattering (RBS), Elastic Recoil Detection Analysis (ERDA), X-ray Photoelectron Spectroscopy (XPS), optical spectroscopy, Raman and Electron Paramagnetic Resonance (EPR). (c) 2005 Elsevier B.V. All rights reserved