This is the first comprehensive book on the engineering of diamond optical devices. It will give readers an up-to-date account of the properties of optical quality synthetic diamond (single crystal, ...nanodiamond and polycrystalline) and reviews the large and growing field of engineering of diamond-based optical devices, with applications in quantum computation, nano-imaging, high performance lasers, and biomedicine. It aims to provide scientists, engineers and physicists with a valuable resource and reference book for the design and performance of diamond-based optical devices.
Recent progress in diamond growth via chemical vapor deposition (CVD) has enabled the manufacture of single crystal samples of sufficient size and quality for realizing Raman laser devices. Here we ...report an external cavity CVD-diamond Raman laser pumped by a Q-switched 532 nm laser. In the investigated configuration, the dominant output coupling was by reflection loss at the diamond's uncoated Brewster angle facets caused by the crystal's inherent birefringence. Output pulses of wavelength 573 nm with a combined energy of 0.3 mJ were obtained with a slope efficiency of conversion of up to 22%.
Coherent coupling between single quantum objects is at the very heart of modern quantum physics. When the coupling is strong enough to prevail over decoherence, it can be used to engineer quantum ...entangled states. Entangled states have attracted widespread attention because of applications to quantum computing and long-distance quantum communication. For such applications, solid-state hosts are preferred for scalability reasons, and spins are the preferred quantum system in solids because they offer long coherence times. Here we show that a single pair of strongly coupled spins in diamond, associated with a nitrogen-vacancy defect and a nitrogen atom, respectively, can be optically initialized and read out at room temperature. To effect this strong coupling, close proximity of the two spins is required, but large distances from other spins are needed to avoid deleterious decoherence. These requirements were reconciled by implanting molecular nitrogen into high-purity diamond. PUBLICATION ABSTRACT
The nitrogen vacancy (NV) center is the most widely studied single optical defect in diamond with great potential for applications in quantum technologies. Development of practical single-photon ...devices requires an understanding of the emission under a range of conditions and environments. In this work, we study the properties of a single NV center in nanodiamonds embedded in an air-like silica aerogel environment which provides a new domain for probing the emission behavior of NV centers in nanoscale environments. In this arrangement, the emission rate is governed primarily by the diamond crystal lattice with negligible contribution from the surrounding environment. This is in contrast to the conventional approach of studying nanodiamonds on a glass coverslip. We observe an increase in the mean lifetime due to the absence of a dielectric interface near the emitting dipoles and a distribution arising from the irregularities in the nanodiamond geometry. Our approach results in the estimation of the mean quantum efficiency (∼0.7) of the nanodiamond NV emitters.
Fluorescent defects in noncytotoxic diamond nanoparticles are candidates for qubits in quantum computing, optical labels in biomedical imaging, and sensors in magnetometry. For each application these ...defects need to be optically and thermodynamically stable and included in individual particles at suitable concentrations (singly or in large numbers). In this Letter, we combine simulations, theory, and experiment to provide the first comprehensive and generic prediction of the size, temperature, and nitrogen-concentration-dependent stability of optically active N−V defects in nanodiamonds.
Control over the quantum states of individual luminescent nitrogen‐vacancy (NV) centres in nanodiamonds (NDs) is demonstrated by careful design of the crystal host: its size, surface functional ...groups, and interfacing substrate. By progressive etching of the ND host, the NV centres are induced to switch from latent, through continuous, to intermittent or “blinking” emission states. The blinking mechanism of the NV centre in NDs is elucidated and a qualitative model proposed to explain this phenomenon in terms of the centre electron(s) tunnelling to acceptor site(s). These measurements suggest that the substrate material and its proximity to the NV are responsible for the fluorescence intermittency.
The emission state of nitrogen‐vacancy (NV) centres in nanodiamonds (NDs) can be manipulated by controlling the size, the surface moieties of the crystal host, and the bandgap structure of the adjacent dielectric environment. These factors also explain the observed luminescence intermittency (“blinking”) of the NV centre in terms of tunnelling of its electron(s) to acceptor site(s) located in the substrate.
Colored diamonds: Despite concerns that photostable luminescent nitrogen‐vacancy (NV) centers do not exist in 5‐nm diamonds, time‐resolved luminescence experiments on weakly bound clusters of such ...diamonds show that NV centers can be embedded (see picture). The efficiency of NV formation scales as the fifth power of the crystal radius.
Coherent population trapping at zero magnetic field was observed for nitrogen-vacancy centers in diamond under optical excitation. This was measured as a reduction in photoluminescence when the ...detuning between two excitation lasers matched the 2.88 GHz crystal-field splitting of the color center ground states. This behavior is highly sensitive to strain, which modifies the excited states, and was unexpected following recent experiments demonstrating optical readout of single nitrogen-vacancy electron spins based on cycling transitions. These results demonstrate for the first time that three-level Lambda configurations suitable for proposed quantum information applications can be realized simultaneously for all four orientations of nitrogen-vacancy centers at zero magnetic field.
Mixed-habit diamonds have experienced periods of growth where they were bounded by two surface forms at the same time. Such diamonds are relatively rare and therefore under-investigated. Under ...certain physical and chemical conditions, smooth octahedral faces grow concurrently with rough, hummocky cuboid faces. However, the specific conditions that cause this type of growth are unknown. Here we present a large array of spectroscopic data in an attempt to investigate the impurity and carbon-isotope characteristics, as well as growth conditions, of 13 large (>6 mm diameter) plates cut from mixed-habit diamonds. The diamonds all generally have high nitrogen concentrations (>1400 ppm), with the octahedral sectors enriched by 127-143% compared to their contemporary cuboid sectors. Levels of nitrogen aggregation are generally low (2-23% IaB) with no significant difference between sectors. IR-active hydrogen features are predominantly found in the cuboid sectors with only very small bands in the octahedral sectors. Platelet characteristics are variable; only one sample shows a large B' band intensity in the octahedral sector, with no platelets occurring in the cuboid sector. Other samples either show a small B' band in both sectors, or just in the cuboid sector, or none at all. These data support a model that shows the concentration-adjusted aggregation rate of nitrogen to be the same in both sectors, whereas the subsequent platelet development is reduced in the cuboid sectors. This is because the interstitial carbon atoms have interacted with disk-crack-like defects only found in cuboid sectors, which in turn reduces their chances of aggregating to form platelets. These disk-crack-like defects are also thought to be the most likely site for the IR-active hydrogen features and they maybe intrinsic to cuboid growth in mixed-habit diamonds. When they are graphitized, as they are in all of the diamonds in this study, this may reflect a heating event prior to volcanic exhumation. Spectroscopic analysis of the green cathodoluminescence exhibited by all of the diamonds shows nickel centers to be present in only the cuboid sectors. Carbon isotope data, obtained by secondary ion mass spectrometry, show very little variation in seven of the diamonds. The total range of 217 analyses is -7.94 to -9.61 (±0.15) per mil, and the largest variation in a single stone is 0.98 per mil. No fractionation in carbon isotopes is seen between octahedral and cuboid sectors at the same growth horizon. These data suggest that the source fluid chemistry, as well as pressure, temperature, and oxygen fugacity were very stable over time, allowing such large volumes of mixed-habit growth to occur. The high concentration of impurities, namely nitrogen and hydrogen, is probably the critical factor required to cause mixed-habit growth. The impurity and isotopic data fall in line with previous modeling based on diamond growth from reduced carbonates with the loss of a 13C-enriched CO2 component.
The necessary elements for practical devices exploiting quantum coherence in diamond materials are summarized, and progress towards their realization documented. A brief review of future prospects ...for diamond-based devices is also provided.
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