Ultrafast manipulation of near field coupling between bright and dark modes in terahertz metamaterial

We demonstrate ultrafast optical control of near field coupling between bright and dark mode resonances in metamaterials. The meta-molecule design consists of two orthogonally twisted resonators tightly coupled through near fields. We place ion implanted silicon patch with ultrafast carrier lifetime inside dark resonator split gap to achieve active control of its fundamental resonance that determines the near field coupling in the meta-molecule. Upon near infrared photoexcitation, we observed ultrafast dynamical transition of near field coupling between bright and dark resonators allowing the meta-molecule to change its state from coupled to decoupled and eventually back to the coupled state.