6 research outputs found
Total absorption of an electromagnetic wave by an overdense plasma
We show both theoretically and experimentally that an electromagnetic wave
can be totally absorbed by an overdense plasma when a subwavelength diffraction
grating is placed in front of the plasma surface. The absorption is due to
dissipation of surface plasma waves (plasmons-polaritons) that have been
resonantly excited by the evanescent component of the diffracted
electromagnetic wave. The developed theoretical model allows one to determine
the conditions for the total absorption.Comment: To be published in PR
Ferroelectric Devices Emit Charged Particles and Radiation
Devices called solid-state ferroelectric- based sources (SSFBSs) are under development as sources of electrons, ions, ultraviolet light, and x-rays for diverse applications in characterization and processing of materials. Whereas heretofore it has been necessary to use a different device to generate each of the aforementioned species of charged particles or radiation, a single SSFBS can be configured and operated to selectively generate any of the species as needed using a single source. Relative to comparable prior sources based, variously, on field emission, thermionic emission, and gaseous discharge plasmas, SSFBSs demand less power, and are compact and lightweight. An SSFBS exploits the unique physical characteristics of a ferroelectric material in the presence of a high-frequency pulsed electric field. The basic building block of an SSFBS is a ferroelectric cathode -- a ferroelectric wafer with a solid electrode covering its rear face and a grid electrode on its front face (see figure). The application of a voltage pulse -- typically having amplitude of several kilovolts and duration of several nanoseconds -- causes dense surface plasma to form near the grid wires on the front surface