An active metamaterials controlled by structured light illumination

The paper reports a novel optical active metamaterials controlled by structured light. In such metamaterials, multiple Au brackets are integrated in its unit-cell; the brackets produce different resonance modes; the metamaterials' properties (bandwidth or frequency) can be controlled by selectively activating one single resonance mode or multiple modes. This control only depends on the spatial distribution of light illumination. We expound the structured light controlling process and the design method of the metamaterials. Based on the method, a bandwidth and frequency tunable terahertz switch and a tunable absorber are designed and evaluated numerically.