Plenary Talk: Applications of electromagnetic metamaterials to vacuum electronics devices and advanced accelerators

The development of high-frequency vacuum electronics structures is hampered by the enormous technological challenges of high-precision three-dimensional machining required for shorter wavelengths. I will describe the possibilities of employing electromagnetic metamaterials (MTMs) to address some of these challenges. In this talk I will first review some of the recent progress in metamaterials-inspired vacuum electronics and accelerating structures. I will then describe two types of metamaterials specifically designed to interact with electron beams. One is the Negative Index Meta-Waveguide (NIMW) [1] that satisfies the following conditions: (a) it is essentially “open” to enable unobstructed electron beam propagation; (b) it supports sub-wavelength modes polarized along the direction of the beam propagation to enable efficient interaction with sub-relativistic (<20keV) electrons; and (c) it is amenable to simple and standard micro-fabrication that does not involve volumetric machining or high-aspect etching because it consists of a stack of metal planes patterned using complementary metamaterial elements (e.g., split rings).