Plasmonic gap modes provide the ultimate confinement of optical fields. Demanding high spatial resolution, the direct imaging of these modes was only recently achieved by electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM). However, conventional 2D STEM-EELS is only sensitive to components of the photonic local density of states (LDOS) parallel to the ...

We have performed high resolution angle-resolved photoemission (ARPES) studies on electron-doped cuprate superconductors Sm2-xCexCuO4 (x=0.10, 0.15, 0.18), Nd2-xCexCuO4 (x=0.15), and Eu2-xCexCuO4 (x=0.15). Imaginary parts of the electron removal self energy show steplike features due to an electron-bosonic mode coupling. The steplike feature is seen along both nodal and antinodal directions but...

A time-dependent approach to the interpretation of resonance Raman scattering intensities has been used to obtain quantitative vibrational mode displacement information from scattering intensities associated with charge-transfer excitation. The displacements and associated frequencies are the key parameters needed to understand Franck-Condon effects in electron-transfer kinetics, and to delinea...

In the CDX-U spherical torus, agreement between radiation temperature and Thomson scattering electron temperature profiles indicates approximately 100% conversion of thermally emitted electron Bernstein waves to the X mode. This has been achieved by controlling the electron density scale length (L(n)) in the conversion region with a local limiter outside the last closed flux surface, shortening...

Y. Yin ( ),1,2,* A. G. Walsh,2 A. N. Vamivakas,3 S. B. Cronin,4 D. E. Prober,5 and B. B Goldberg2,3,† 1Key Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China 2Department of Physics, Boston University, Boston, Massachusetts 02215, USA 3Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, USA ...

ultrasoundelastographyisanon-invasivemethodwhichimagestheelasticityofsoft-tissues. tomakeanimage, preandafterasmallcompression, ultrasoundradio frequency(rf)signalsareacquiredandthetimedelaysbetweenthemareestimated. thefirstdifferentiationofdisplacementestimationsiscalledelastogram. inthisstudy, wearegoingtomakeanelastogramusingtheprocessingmethodnamed empirical mode decomposition (emd). emdisa...

We report the testing of a high gradient electron accelerator with a photonic-band-gap (PBG) structure. The photonic-band-gap structure confines a fundamental TM(01)-like accelerating mode, but does not support higher-order modes (HOM). The absence of HOM is a major advantage of the PBG accelerator, since it suppresses dangerous beam instabilities caused by wakefields. The PBG structure was des...

An electron beam passing through a metamaterial structure is predicted to generate reversed Cherenkov radiation, an unusual and potentially very useful property. We present an experimental test of this phenomenon using an intense electron beam passing through a metamaterial loaded waveguide. Power levels of up to 5 MW are observed in backward wave modes at a frequency of 2.40 GHz using a one mi...

The first detailed experimental study of an instability driven by the presence of a finite ion fraction in an electron-rich non-neutral plasma confined on magnetic surfaces is presented. The instability has a poloidal mode number m=1, implying that the parallel force balance of the electron fluid is broken and that the instability involves rotation of the entire plasma, equivalent to ion-resona...

The quasi two-dimensional electron gas on a metal film can transmit to the surface even minute mechanical disturbances occurring in the depth, thus allowing the gentlest of all surface probes, helium atoms, to perceive the vibrations of the deepest atoms via the induced surface-charge density oscillations. A density functional perturbation theory (DFPT) and a helium atom scattering study of the...