Optical switch and modulator devices are described, usable for Terahertz data communication rates. The device comprising an optically transmissive substrate configured for propagating electromagnetic radiation therethrough and a metamaterial arrangement optically coupled to said substrate. The metamaterial arrangement comprises at least one layer of metamaterial particles optically coupled to at least some portion of said optically transmissive substrate, and at least one nanomesh layer made of at least one electrically conducting material placed over at least some portion of the at least one metamaterial layer. The at least one nanomesh layer configured to discharge electrons into the at least one metamaterial layer responsive to electromagnetic or electric signals applied to the metamaterial arrangement, and the at least one metamaterial layer configured to change from an optically opaque state into an optically transparent state upon receiving the discharged electrons, to thereby at least partially alter electromagnetic radiation passing through the substrate.