Structural Control of Metamaterial Oscillator Strength and Electric Field Enhancement at Terahertz Frequencies
Journal Article

Published: Friday, August 29, 2014 1406.1127
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Authors (5 total): G. R. Keiser, H. Seren, A. C. Strikwerda, X. Zhang, R. Averitt

Abstract: The design of artificial nonlinear materials requires control over the internal resonant charge densities and local electric field distributions. We present a MM design with a structurally controllable oscillator strength and local electric field enhancement at terahertz frequencies. The MM consists of a split ring resonator (SRR) array stacked above an array of nonresonant closed conducting rings. An in-plane, lateral shift of a half unit cell between the SRR and closed ring arrays results in a decrease of the MM oscillator strength by a factor of 4 and a 40% change in the amplitude of the resonant electric field enhancement in the SRR capacitive gap. We use terahertz time-domain spectroscopy and numerical simulations to confirm our results and we propose a qualitative inductive coupling model to explain the observed electromagnetic reponse.