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We propose a simple and original implementation of the BB84 quantum key distribution protocol via a quantum frequency-translation process in a nonlinear optical fiber. Unlike most conventional quantum key distribution implementations, which rely on the photon polarization/phase, encoding quantum information in the photon frequency state is inherently more stable against mechanical and/or thermal fluctuations over transmission media such as optical fibers. We also show the proposed scheme to be naturally expandable to larger character sets, and demonstrate a straightforward extension to a four-character alphabet (qu-quarts), providing enhanced security for quantum key distribution applications. [ABSTRACT FROM AUTHOR]

We have recently introduced a new modeling equation for the propagation of pulses in optical waveguides, the photon-conserving Nonlinear Schrödinger Equation (pcNLSE) which, unlike the canonical NLSE, guarantees strict conservation of both the energy and the number of photons for any arbitrary frequency-dependent nonlinearity. In this paper, we analyze some properties of this new equation in the familiar case where the nonlinear coefficient of the waveguide does not change sign. We show that the pcNLSE effectively adds a correction term to the NLSE proportional to the deviation of the self-steepening (SS) parameter from the photon-conserving condition in the NLSE. Furthermore, we describe the role of the self-steepening parameter in the context of the conservation of the number of photons and derive an analytical expression for the relation of the SS parameter with the time delay experienced by pulses upon propagation. Finally, we put forth soliton-like solutions of the pcNLSE that, unlike NLSE solitons, conserve the number of photons for any arbitrary SS parameter. [ABSTRACT FROM AUTHOR]

Identification of catastrophic events recorded as resedimented deep marine deposits can be challenging because of multiple possible triggering mechanisms. This study investigates seismo‐turbidites (STs) deposited in the Ionian Sea as a consequence of major historical earthquakes related to the Calabrian Arc subduction system. Taking advantage of the available sedimentological reconstructions, we focused our analysis on high‐resolution X‐ray fluorescence core scanner (XRF‐CS), organic carbon and isotopic data to define geochemical signatures characterizing the ST units. The relationships between geochemical and sedimentological proxies were statistically tested using Pearson correlation and principal component analysis (PCA). Up to ∼78% of the total variance in the data set can be reduced to three principal components which identified four elemental ratio groups associated to the degree of terrestrial/coastal influence in each major depositional unit (i.e., pelagic, ST sandy stacked units, homogenites, tsunamite‐seiche laminites, and tsunamite backwash). The sample score results were evaluated together with organic carbon data in order to assess geochemical variability throughout the composite turbidite structure in different basins settings. The basal parts of the ST contain coarse‐grained sediment stacks whose sources can be traced back and sedimentary processes (surficial sediment erosion/massive slope failures) can be defined using geochemical data. The topmost parts of the STs exhibit a mixed compositional character suggesting basin‐wide processes such as seiche oscillations and tsunami wave erosion/backwashing. The application of selected XRF‐CS based elemental ratios as proxies in paleoseismological studies can help reconstruct the seismic history of a continental margin. Plain Language Summary: Submarine paleoseismology is a widely applied method to reconstruct seismicity back in time in tectonically active regions. The Calabrian Arc in the Ionian Sea is a subduction system related to the convergence between Africa and Eurasia plates which produces uplifting coastal mountains, enhances discharge of sediments on the continental shelf and induces the frequent occurrence of earthquakes. Seismic shaking is often associated with submarine slope failures, tsunamis and deposition of seismo‐turbidites which represent more than 90% of total sedimentation in the deep Mediterranean basins. We analyzed physical and geochemical data of sediment samples through a statistical approach to identify elemental ratio groups bringing information on the difference between the interseismic and co‐seismic sedimentary processes, as well as the degree of terrestrial/coastal influence in marine sediments. The proposed statistical approach can be used for sediment characterization, in absence of other analytical data, providing fast information on sedimentary processes and ultimately on the seismic history of the continental margin. Key Points: Analysis of elemental, organic carbon, and isotopic data from seismo‐turbidites provides information on source to sink processesStatistical analysis of physical and geochemical variables enhances correlation of earthquake‐triggered depositsThe application of selected geochemical proxies in paleoseismological studies can be very effective in reconstructing past seismicity [ABSTRACT FROM AUTHOR]

We are developing of arrays of membrane isolated resonator-bolometers, each with a kinetic inductance device (KID) to measure the temperature of the membrane. The KIDs are fabricated out of the high temperature superconductor YBCO to allow operation at relatively high temperatures. The bolometers are designed to offer higher sensitivity than sensors operating at 300 K, but they require less expensive and lighter weight cooling than even more sensitive conventional superconducting detectors operating at lower temperatures. The bolometer arrays are applicable as focal planes in infrared imaging spectrometers, such as for planetary science missions or earth observing satellites. We describe the devices and present measurements of their sensitivity. [ABSTRACT FROM AUTHOR]

Summary: This research introduces and evaluates a novel method that offers the potential of providing objective criteria to forensic microscopical hair comparisons. The method combines hair diameter with numeric characterisations of red, green, and blue colour content as determined with the use of digital imaging at defined locations of the hair. Thirty hairs were collected from each of twenty participants, all with naturally coloured brown hair. The hairs were examined with an Olympus BX53® polarising light microscope and digital images were viewed with an Olympus DP72® camera under 400× magnification. Using Olympus cellSens™ Entry software, hair diameter was measured at 1000, 1500 and 2000 μm from the base of the root. The Olympus cellSens™ Entry software uses a red, green and blue (RGB) colour model to quantitatively define the colour of each pixel on an image based on its composition of these three principal colour components. This software was used to collect numerical characterisations of hair colour at each distance interval. The diameter and colour values for each hair were compared using discriminant analysis (DA) and principal component analysis. Although a large amount of intrapersonal variation was observed, the degree of interpersonal variation was greater and enabled the statistical model to differentiate between the hair samples from each participant. The DA model achieved sample reclassification with an error rate of 7.33%. A validation study was conducted on a subset of hair samples from which 18 of the 20 were correctly assigned to the participant from whom they originated. These results support the potential of this method to provide an objective addition to current microscopical hair comparison practices. [ABSTRACT FROM AUTHOR]

Full models of scalar modulation instability (MI) in optical fibers available in the literature usually involve complex formulations. In this paper, we present a novel approach to the analysis of MI in optical fibers by means of a simple geometrical description in the power versus frequency plane. This formulation allows us to relate the shape of the MI gain to any arbitrary dispersion profile of the medium, thus providing a simple insight. As a result, we derive a straightforward explanation of the nontrivial dependence of the cutoff power on high-order dispersion and explicitly derive the power that maximizes the gain. Our approach puts forth a tool to synthesize a desired MI gain with the potential application to a number of parametric-amplification and supercontinuum-generation devices whose initialstage dynamics rely upon MI. [ABSTRACT FROM AUTHOR]

We study the performance of 2D-decorated nanowires in heralded single-photon sources within the framework of a recently introduced master equation for nonlinear waveguides. We put forth a complete analysis that includes the frequency dependence of the nanowire's loss, chromatic dispersion, and (complex) nonlinear coefficient, and show that the graphene-oxide-decorated nanowire behaves as an almost ideal probabilistic single-photon source. Finally, we believe these results to be of relevance as they point to the great potential of 2D-decorated nanowires in integrated-photonic devices for applications in quantum technologies. • Heralded single-photon sources (HSPSs) can be implemented with silicon nanowires. • Graphene-oxide-decorated nanowires are good candidates for probabilistic HSPSs. • The performance of HSPSs can be estimated with a novel master equation approach. [ABSTRACT FROM AUTHOR]

We describe the transition-edge-sensor (TES) focal plane arrays used for three cosmic microwave background (CMB) polarimetry projects. The first is BICEP2. The focal plane array for BICEP2 has been delivered and the instrument is now taking data at the South Pole. Second is the Keck Array. The focal planes for Keck will be nearly identical to those of BICEP2, but will cover multiples frequencies (96, 150 and 225 GHz). The scheduled deployment of Keck is late 2010. Finally, there is Spider, a high-altitude balloon observatory, which will also cover 96, 150, and 225 GHz and will be deployed in 2012. The goal of all three experiment is detecting B modes in the polarization of the CMB. [ABSTRACT FROM AUTHOR]

We have developed antenna-coupled transition-edge sensor (TES) bolometers for a wide range of cosmic microwave background (CMB) polarimetry experiments, including BICEP2, Keck Array, and the balloon borne SPIDER. These detectors have reached maturity and this paper reports on their design principles, overall performance, and key challenges associated with design and production. Our detector arrays repeatedly produce spectral bands with 20%-30% bandwidth at 95, 150, or 220~GHz. The integrated antenna arrays synthesize symmetric co-aligned beams with controlled side-lobe levels. Cross-polarized response on boresight is typically ~0.5%, consistent with cross-talk in our multiplexed readout system. End-to-end optical efficiencies in our cameras are routinely 35% or higher, with per detector sensitivities of NET~300 uKrts. Thanks to the scalability of this design, we have deployed 2560 detectors as 1280 matched pairs in Keck Array with a combined instantaneous sensitivity of ~9 uKrts, as measured directly from CMB maps in the 2013 season. Similar arrays have recently flown in the SPIDER instrument, and development of this technology is ongoing., Astronomy

In this Letter we introduce a novel equation addressing the effect of quantum noise in optical fibers with arbitrary frequency-dependent nonlinear profiles. To the best of our knowledge, such an endeavor has not been undertaken before despite the growing relevance of fiber optics in the design of new quantum devices. We show that the stochastic generalized nonlinear Schrödinger equation, derived from a quantum theory of optical fibers, leads to unphysical results such as a negative photon number and the appearance of a dominant anti-Stokes sideband when applied to this kind of waveguides. Starting from a recently introduced master-equation approach to propagation in fibers, we derive a novel stochastic photon-conserving nonlinear Schrödinger equation suitable for modeling arbitrary nonlinear profiles, thus greatly enhancing the study of fiber-based quantum devices. [ABSTRACT FROM AUTHOR]

• The temporal analogue of refraction and reflection in optical fibers can be extended to schemes resembling a temporal laser. • A temporal laser provides a novel method to the all-optical generation of a pulse train of adjustable period. • Each pulse of the train generated with a temporal laser contains information about the fiber parameters at the point at which it was created, allowing for a distributed-sensing of that parameters. We propose a novel scheme for the all-optical generation of pulse trains in optical fibers based on the reflection and refraction of pulses at a time boundary, and the temporal analogue of a laser cavity with gain. Furthermore, this scheme is shown to provide an original and simple way to measure distributed fiber parameters. In particular, we put forth an application of the temporal laser to the distributed sensing of the fiber group-velocity dispersion parameter. [ABSTRACT FROM AUTHOR]