Plasma modification of spoof plasmon propagation along metamaterial-air interfaces

摘要

We report on measurements of the shift in resonance frequency of "spoof surface plasmon polariton propagation along a 2-D metamaterial slow-wave structure induced by a gaseous plasma near the metamaterial/air interface. A transmission line circuit model for the metamaterial structure interprets the introduction of a plasma as a decrease in unit cell capacitance, causing a shift in the plasmon dispersion to higher frequency. We show through simulations and experiments that the effects of this shift at the resonance frequency and attenuation below and above resonance depend on the plasma density. The shifts recorded experimentally are small owing to the low plasma densities generated near the structure, ～10~(11) cm~(-3), but simulations show that a shift of ～3% of the resonance frequency can be generated at plasma densities of ～10~(12) cm~(-3).