13 research outputs found

    Integrating diamond with GaN photonic device

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    The nitrogen vacancy is a photostable emitter in diamond which is optically accessible at room temperature and a potential candidate for quantum information processing as a spin register. The challenge facing research today is the efficient collection and manipulation of the NV’s emissions, such as enhancing the zero phonon line transitions for a coherent spin-photon interface. This project focuses on integrating ultra-thin diamond membranes with established photonic devices. By bonding the diamond to GaN, for example, mode simulations show that light can be coupled significantly into and out of the defect allowing processing across large area PICs

    Biomacromolecular stereostructure mediates mode hybridization in chiral plasmonic nanostructures

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    The refractive index sensitivity of plasmonic fields has been exploited for over 20 years in analytical technologies. While this sensitivity can be used to achieve attomole detection levels, they are in essence binary measurements that sense the presence/absence of a predetermined analyte. Using plasmonic fields, not to sense effective refractive indices but to provide more “granular” information about the structural characteristics of a medium, provides a more information rich output, which affords opportunities to create new powerful and flexible sensing technologies not limited by the need to synthesize chemical recognition elements. Here we report a new plasmonic phenomenon that is sensitive to the biomacromolecular structure without relying on measuring effective refractive indices. Chiral biomaterials mediate the hybridization of electric and magnetic modes of a chiral solid-inverse plasmonic structure, resulting in a measurable change in both reflectivity and chiroptical properties. The phenomenon originates from the electric-dipole–magnetic-dipole response of the biomaterial and is hence sensitive to biomacromolecular secondary structure providing unique fingerprints of α-helical, β-sheet, and disordered motifs. The phenomenon can be observed for subchiral plasmonic fields (i.e., fields with a lower chiral asymmetry than circularly polarized light) hence lifting constraints to engineer structures that produce fields with enhanced chirality, thus providing greater flexibility in nanostructure design. To demonstrate the efficacy of the phenomenon, we have detected and characterized picogram quantities of simple model helical biopolymers and more complex real proteins

    Different paths to the modern state in Europe: the interaction between domestic political economy and interstate competition

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    Theoretical work on state formation and capacity has focused mostly on early modern Europe and on the experience of western European states during this period. While a number of European states monopolized domestic tax collection and achieved gains in state capacity during the early modern era, for others revenues stagnated or even declined, and these variations motivated alternative hypotheses for determinants of fiscal and state capacity. In this study we test the basic hypotheses in the existing literature making use of the large date set we have compiled for all of the leading states across the continent. We find strong empirical support for two prevailing threads in the literature, arguing respectively that interstate wars and changes in economic structure towards an urbanized economy had positive fiscal impact. Regarding the main point of contention in the theoretical literature, whether it was representative or authoritarian political regimes that facilitated the gains in fiscal capacity, we do not find conclusive evidence that one performed better than the other. Instead, the empirical evidence we have gathered lends supports to the hypothesis that when under pressure of war, the fiscal performance of representative regimes was better in the more urbanized-commercial economies and the fiscal performance of authoritarian regimes was better in rural-agrarian economie

    Different Paths to the Modern State in Europe: The Interaction between Domestic Political Economy and Interstate Competition

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    Progress in compact room temperature THz radiation sources

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    There is currently a great deal of interest in the development of efficient compact sources of terahertz (THz) radiation. There are many factors of device and materials design which are still under ongoing improvement with the aim of producing an efficient, high power, room-temperature THz signal emission device which is tunable over a practical THz frequency range. The recent advances in production of various room-temperature THz radiation sources are reviewed with particular emphasis on photomixer antenna devices, and recent patents on technology and methods relating to: pulsed and continuous wave (CW) THz generation via nonlinear crystals; quantum cascade lasers (QCLs); ultrafast diodes and photodiodes; and heterodyne sources are discussed
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