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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Diamond Functionalization by Ultrafast Laser Pulses
摘要： The extreme material properties of diamond make it an attractive candidate for many technological applications. However, these same material properties often prove disruptive to the machining of diamond into functional devices. Ultrashort laser pulses focused inside diamond offer a potential new route for the functionalisation of diamond, offering a range of fabrication modalities on a single platform. Focusing beneath the surface of diamond, there is sufficient intensity from ultrashort laser pulses for non-linear absorption of light, which can lead to modification of the diamond lattice. The non-linearity of the process confines the modification to the focal volume of the laser, without effecting the diamond surface or surrounding regions. At high pulse energies (above ~100nJ), the laser deposits sufficient energy to break down the diamond lattice and induce a graphitic phase. Tracing the diamond through the laser focus allows the creation of conductive graphitic wires embedded inside the diamond in 3D. The processing becomes deterministic and the wire conductivity increases when the fabrication is carried out at high numerical apertures (NA = 1.4) [1]. The large refractive index mismatch at the diamond surface generates a depth dependent spherical aberration which should be corrected using adaptive optics. The laser written electrical wires can be used to fabricate radiation sensors, as shown in Fig. 1(a), which benefit from the radiation hardness of diamond. The advances in laser fabrication allow the realisation of new detector geometries. The graphitic inclusions fabricated by ultrashort pulse lasers beneath the surface of diamond exert stress on the surrounding diamond, which in turn modifies the optical properties of the crystal. By designing stress fields, it is possible to fabricate optical waveguides [2] and waveguide Bragg gratings [3] inside the diamond. In a different fabrication regime, it is also possible functionalise the diamond using ultrashort pulses without causing breakdown of the diamond lattice. We have shown that with a single ultrashort pulse it is possible to generate an ensemble of vacancies at the laser focus inside the diamond. A thermal anneal process heals any damage to the lattice and is successful in forming highly coherent isolated single nitrogen vacancy (NV) colour centres [4, 5]. We have recently demonstrated improvements to the method using a laser based localised anneal with fluorescence feedback to write arrays of NV centres with near unity yield and in-plane positioning accuracy of 40nm [6].
关键词： functionalisation,diamond,graphitic wires,ultrafast laser pulses,NV centres,optical waveguides
更新于2025-09-11 14:15:04
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Tunable self‐powered n‐SrTiO <sub/>3</sub> photodetectors based on varying CuS‐ZnS nanocomposite film (p‐CuZnS, p‐CuS, and n‐ZnS)
摘要： Dense Boron-doped diamond (BDD) composites were fabricated by high pressure and high-temperature sintering (HPHT) at 5 GPa and 1450 °C for 300 s in presence of Al, B and C as sintering additives. Phase compositions, microstructures, and electrochemical performances of sintered specimens were investigated by X-ray di?raction (XRD), scanning electron microscopy (SEM), and electrochemistry. Results suggested that Al3BC3 and Al4C were formed by in-situ reaction between sintering additives and diamond, which can promote densi?cation of BDD. In addition, BDD composites containing 10 wt% sintering additives exhibited the highest electrical resistivity (4.40 × 10?4 Ω m) and hole concentration (4.55 × 1025/m3). The working potential windows of BDD composite electrodes in 0.1 M H2SO4, 0.1 M Na2SO4 and 0.1 M NaOH electrolytes were estimated to 1.9 V, 2.9 V and 2.3 V, respectively. Electron transfer coe?cients of composite electrodes approached 0.5, con?rming good reversibility. Finally, methylene blue was completely degraded by BDD composite electrodes within 120 min using NaCl as supporting electrolyte.
关键词： High-pressure and high-temperature sintering,Boron-doped diamond,Electrochemical performances
更新于2025-09-11 14:15:04
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Study of Electrode Fabrication in Diamond with a Femto‐Second Laser
摘要： Diamond is a radiation hard material, which makes it suitable for its use in high energy physics experiments as a particle detector. To further reduce the effects of radiation damage, diamond detectors can be fabricated by inscribing graphitic electrodes perpendicular to the surface—the so-called 3D detectors. This can be done via processing with a femtosecond laser. Herein, a systematic study of the cross section of the graphitic wires inscribed into diamond is shown as a function of laser pulse energy, stage translational speed and, for the ?rst time, polarization for a single crystal and polycrystalline chemical vapour deposition (CVD) diamond samples. No dependence of the electrode width with speed polarization and sample for the same pulse energies within uncertainties are observed. The graphitic content of the electrodes is studied in terms of Raman spectrometry: no clear dependence on the fabrication parameters studied is observed.
关键词： femtosecond lasers,3D,radiation sensors,diamond,sensor fabrication,graphites
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Toward Coupling Color Centers in Single Crystal Diamond to Two-Dimensional Materials
摘要： Individual nitrogen vacancy (NV) color centers in diamond are bright, photo-stable, atomic-sized dipole emitters [1]. Consequently, they represent optimal candidates for novel scanning near field microscopy techniques [2]. Here, NV centers form one member of a F¨orster Resonance Energy Transfer (FRET) pair. Due to their broadband emission (> 100 nm), NVs are versatile donors for FRET to systems absorbing in the near infrared spectral range. Highly-promising applications include, e.g., nanoscale imaging of fluorescent molecules or nanomaterials like graphene [2]. Critical parameters for FRET are the NV’s quantum efficiency, charge state stability and NV-sample-distance. Previous experiments used NVs in nanodiamond for FRET [2], however these NVs might suffer from quenching, instability and badly controlled surface termination. We here address this issue by using shallowly implanted NV centers in optimized cylindrical nanostructures [3] used as scanning probes in our homebuilt combination of a confocal and an atomic force microscope. In recent years, two-dimensional materials especially monolayers of semiconducting materials are of major interest in research. Particularly, dichalcogenides like, e.g., tungsten diselenide (WSe2) are promising candidates for a varity of applications [4]. WSe2 emits photons at a wavelength of around 750 nm while absorbing photons below 700 nm [4] which renders WSe2 as a promising FRET partner for NV centers. Here, we present first results towards demonstrating the interaction of NV color centers in single crystal diamond with WSe2. We envisage using quenching of the NV center sued as a donor in FRET in close proximity to the 2D material as a valuable sensing ressource.
关键词： F¨orster Resonance Energy Transfer (FRET),tungsten diselenide (WSe2),nitrogen vacancy (NV) color centers,diamond,two-dimensional materials
更新于2025-09-11 14:15:04
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Research on the mechanism of micromachining of CVD diamond by femtosecond laser
摘要： Diamond is an excellent material in terms of hardness, thermal conductivity and chemical stability. In order to broaden its application area, the interaction mechanism of CVD diamond processed by femtosecond laser is analyzed based on laser micromachining technology. Through the threshold theory, the ablation threshold of CVD diamond is calculated. At the same time, the graphitization phase transition occurred in the diamond. The internal elements before and after the ablation of diamond by femtosecond laser are characterized by X-ray energy spectrum analysis. The changes of element content and bonding form are analyzed, and the relevant graphitization mechanism is revealed.
关键词： XPS,graphitization,ablation,CVD diamond,Femtosecond laser
更新于2025-09-11 14:15:04
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Inkjet seeded CVD-grown hydrogenated diamond gas sensor under UV-LED illumination
摘要： Hydrogen-terminated diamond gas sensors have been prepared by selective deposition of nanodiamond ink using direct inkjet printing on interdigital electrodes, followed by chemical vapor deposition growth of a nanoctrystalline diamond layer. The structure of the deposited layer was characterised and analyzed by scanning electron microscopy and Raman spectroscopy. The effect of ultraviolet light-emitting diode (UV-LED) illumination on the performance of the hydrogen-terminated diamond gas sensor with regard to reducing (NH3) and oxidizing (NO2) gases at various temperatures was studied. UV-LED illumination showed a short response / recovery time to NH3 and NO2 gases, 97 s / 153 s, and 72 s / 186 s respectively.
关键词： UV light,gas sensor,inkjet printing,hydrogenated-diamond
更新于2025-09-11 14:15:04
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Field emission microscopy pattern of a single-crystal diamond needle under ultrafast laser illumination
摘要： We report herein on the spatial beam properties of a ?eld emission electron source based on a single-crystal diamond needle illuminated by ultrashort light pulses. We show that the increasing of the laser intensity strongly modi?es the emission pattern, leading to the emergence of a new emission region at high peak power. This region is situated on the opposite side of the diamond needle to the one irradiated by the laser. By spatially-resolved energy spectrometry, we prove that the electrons emitted from this region are governed by a multi-photon absorption process. The occurrence of this emission pattern can be explained by accounting for the inhomogeneous distribution of the optical ?eld enhancement and the laser absorption induced by light diffraction within the nanometric needle. The numerical simulations performed on a real sub-wavelength tip con?rm this localization of the optical ?eld enhancement and reveal that the electrons trajectories match the spatial beam distribution evidenced experimentally. This work underlines the need to closely monitor the surface roughness of the ?eld emitter as well as the laser illumination conditions to ?nely control its emission pattern.
关键词： ?eld emission,diamond,ultrafast laser,electron spectroscopy,nanoemitters
更新于2025-09-11 14:15:04
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Sub-GHz linewidths ensembles of SiV centers in a diamond nano-pyramid revealed by charge state conversion
摘要： Producing nano-structures with embedded bright ensembles of lifetime-limited emitters is a challenge with potential high impact in a broad range of physical sciences. In this work, we demonstrate controlled charge transfer to and from dark states exhibiting very long lifetimes in high density ensembles of SiV centers hosted in a diamond nano-pyramid grown by chemical vapor deposition. Further, using a combination of resonant photoluminescence excitation and a frequency-selective persistent hole burning technique that exploits this charge state transfer, we could demonstrate close to lifetime-limited linewidths from the SiV centers. Such a nanostructure with thousands of bright narrow linewidth emitters in a volume much below λ3 will be useful for coherent light-matter coupling, for biological sensing, and nanoscale thermometry.
关键词： Color centers,Diamond,Silicon Vacancy centers,photoionisation,photoluminescence
更新于2025-09-11 14:15:04
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Femtosecond-laser-ablation induced transformations in the structure and surface properties of diamond-like nanocomposite films
摘要： Femtosecond laser ablation processing is applied for surface modification and micropatterning of diamond-like nanocomposite (DLN) films (a-C:H:Si:O films). Using a visible femtosecond laser (wavelength 515 nm, pulse duration 320 fs), microgroove patterns have been fabricated on the DLN films, aimed at further studies of their properties. The studies were focused on (i) structural transformations in the surface layers using Raman spectroscopy and transmission electron microscopy (TEM), (ii) wettability of laser-patterned films, and (iii) nano/microscale friction properties of laser-patterned DLN films using lateral force microscopy. Raman spectroscopy and TEM data showed characteristic features of the surface graphitization during ultrashort-pulse ablation. High resolution TEM study of the microgrooves revealed the formation of cubic SiC nanocrystals (4–8 nm size) on the laser-ablated surface. The water contact angle measurements showed anisotropic wetting behavior of the grooved surfaces (the contact angle was different in the directions parallel and perpendicular to microgrooves), depending on the groove depth (aspect ratio). Lateral force microscopy examination (with micro-sized Si tips) showed that the laser-patterned regions exhibited low friction properties compared to the original surface. The obtained results demonstrate that femtosecond laser processing is an effective technique to generate new properties of hard DLN coatings at the micro and macroscale.
关键词： Diamond-like nanocomposite films,Femtosecond laser ablation,Micropatterning,SiC nanocrystals,Graphitization,Wettability
更新于2025-09-11 14:15:04
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Effects of diamond-like carbon thin film and wrinkle microstructure on cell proliferation
摘要： This paper aims to clarify the effects of diamond-like carbon (DLC) thin film and the wrinkle microstructure formed by depositing the DLC thin film on a poly(dimethylsiloxane) (PDMS) substrate on cell proliferation with a view to applying to cell scaffolds, which are essential technologies to control cellular activity and behaviors for cell therapy and therapeutic applications. Mouse myoblast cell (C2C12) culture tests using substrates with/without the DLC thin film and the wrinkle microstructure revealed that the cell proliferation was largely enhanced by the existence of the DLC thin film on the substrate. Moreover, it was examined how the size of the wrinkle of the DLC thin film deposited PDMS substrates affected cellular growth, and it was found that the wrinkle microstructure had the optimum range of the height difference of the wrinkle, from 0.7 to 1.0 μm as the surface roughness (Rc), for promoting cell proliferation.
关键词： Wrinkle microstructure,PDMS,Diamond-like carbon,Cell proliferation
更新于2025-09-11 14:15:04