Abstract: Method and apparatus for modulation of both the intensity and the polarization of radiation in silicon waveguides by applying a biasing voltage to the waveguide.

Abstract: A surface-emission cathode formed on an insulating surface having cantilevered, i.e. “undercut,” electrodes. Suitable insulating surfaces include negative electron affinity (NEA) insulators such as glass or diamond. The cathode can operate in a comprised vacuum (e.g., 10?7 Torr) with no bias on the electrodes and low vacuum electric fields (e.g., at least 10 V cm?1). Embodiments of the present invention are inexpensive to fabricate, requiring lithographic resolution of approximately 10 micrometers. These cathodes can be formed over large areas for use in lighting and displays and are suitable for satellite applications, such as cathodes for tethers, thrusters and space-charging neutralizers.