Electrical modulation of the optical properties of mid-infrared metamaterials

We present a hybrid, mid-infrared metamaterial device, consisting of a near-surface semiconductor quantum well beneath a gold split ring resonator array. Electrical control of the free carrier concentration in the near-surface quantum well allows variation of the refractive index within the fringing field of the split ring resonator array. We observe a 10% transmission change at the fundamental resonance of the split ring resonators, in very good agreement with simulations. For optimised structures, we predict a 10% wavelength shift of the fundamental resonance, with important implications for optical components such as switches and spatial light modulators.