Electro-optic tuning of split ring resonators embedded in a liquid crystal

Two-dimensional arrays of split ring resonators for near-infrared frequencies are embedded in a liquid crystal (LC) and the influences of LC alignment, temperature, and electric fields on the resonance frequencies are studied. The results show that tunability can not only be achieved by influencing the state of polarization of the incident radiation, but also by direct interaction of the evanescent field of the resonant modes with the LC. Depending on the LC alignment, the field-induced shift of the resonance frequency is found to vary for different excited modes. Some guidelines for the design of tunable frequency selective metasurfaces can be deduced from these experimental results.