An Evaluation of the Optical Maser Photon Rate Gyroscope

Mathematical development of resonant frequencies of electromagnetic cavity - Evaluation of optical maser photon rate gyroscop

Optical Maser Photon Rate Gyroscope

Resonant frequency equations for optical maser photon rate gyroscope desig

Finite element formulation for linear thermoviscoelastic materials

Report presents the finite difference equations in time and finite element matrix equations in space for general linear thermovisoelastic problems. The equations are derived for a general three-dimensional body but are applicable to one- and two-dimensional configurations with minor changes

Pressure seal Patent

Pressure seals suitable for use in environmental test chamber

Landau level spectroscopy of ultrathin graphite layers

Far infrared transmission experiments are performed on ultrathin epitaxial graphite samples in a magnetic field. The observed cyclotron resonance-like and electron-positron-like transitions are in excellent agreement with the expectations of a single-particle model of Dirac fermions in graphene, with an effective velocity of c* = 1.03 x 10^6 m/s.Comment: 4 pages 4 figures Slight revisions following referees' comments. One figure modifie

Few layer graphene on SiC, pyrolitic graphite and graphene: a Raman scattering study

The results of micro-Raman scattering measurements performed on three different ``graphitic'' materials: micro-structured disks of highly oriented pyrolytic graphite, graphene multi-layers thermally decomposed from carbon terminated surface of 4H-SiC and an exfoliated graphene monolayer are presented. Despite its multi-layer character, most parts of the surface of the graphitized SiC substrates shows a single-component, Lorentzian shape, double resonance Raman feature in striking similarity to the case of a single graphene monolayer. Our observation suggests a very weak electronic coupling between graphitic layers on the SiC surface, which therefore can be considered to be graphene multi-layers with a simple (Dirac-like) band structure.Comment: 4 pages, 3 Figures Structure of the paper strongly modified, small changes in Fig 2 and 3. Same interpretation and same result

Experimental observation of nanoscale radiative heat flow due to surface plasmons in graphene and doped silicon

Owing to its two dimensional electronic structure, graphene exhibits many unique properties. One of them is a wave vector and temperature dependent plasmon in the infrared range. Theory predicts that due to these plasmons, graphene can be used as a universal material to enhance nanoscale radiative heat exchange for any dielectric substrate. Here we report on radiative heat transfer experiments between SiC and a SiO2 sphere which have non matching phonon polariton frequencies, and thus only weakly exchange heat in near field. We observed that the heat flux contribution of graphene epitaxially grown on SiC dominates at short distances. The influence of plasmons on radiative heat transfer is further supported with measurements for doped silicon. These results highlight graphenes strong potential in photonic nearfield and energy conversion devices.Comment: 4 pages, 3 figure

Weak antilocalization in epitaxial graphene: evidence for chiral electrons

Transport in ultrathin graphite grown on silicon carbide is dominated by the electron-doped epitaxial layer at the interface. Weak anti-localization in 2D samples manifests itself as a broad cusp-like depression in the longitudinal resistance for magnetic fields 10 mT$< B <$ 5 T. An extremely sharp weak-localization resistance peak at B=0 is also observed. These features quantitatively agree with graphene weak-(anti)localization theory implying the chiral electronic character of the samples. Scattering contributions from the trapped charges in the substrate and from trigonal warping due to the graphite layer on top are tentatively identified. The Shubnikov-de Haas oscillations are remarkably small and show an anomalous Berry's phase.Comment: 5 pages, 4 figures. Minor change

Tuning the electron-phonon coupling in multilayer graphene with magnetic fields

Magneto Raman scattering study of the E$_{2g}$ optical phonons in multi-layer epitaxial graphene grown on a carbon face of SiC are presented. At 4.2K in magnetic field up to 33 T, we observe a series of well pronounced avoided crossings each time the optically active inter Landau level transition is tuned in resonance with the E$_{2g}$ phonon excitation (at 196 meV). The width of the phonon Raman scattering response also shows pronounced variations and is enhanced in conditions of resonance. The experimental results are well reproduced by a model that gives directly the strength of the electron-phonon interaction.Comment: 4 pages, 3 figure

Magneto-transmission of multi-layer epitaxial graphene and bulk graphite: A comparison

Magneto-transmission of a thin layer of bulk graphite is compared with spectra taken on multilayer epitaxial graphene prepared by thermal decomposition of a SiC crystal. We focus on the spectral features evolving as \sqrt{B}, which are evidence for the presence of Dirac fermions in both materials. Whereas the results on multi-layer epitaxial graphene can be interpreted within the model of 2D Dirac fermions, the data obtained on bulk graphite can only be explained taking into account the 3D nature of graphite, e.g. by using the standard Slonczewski-Weiss-McClure model.Comment: 5 pages, 2 figure