Tunable metamaterials with negative permeability in THz range

We report on metamaterials which exhibit a tunable interval of negative effective permeability within 0.2-0.36 THz. They consist of a strontium titanate platelet, which shows a high and temperature tunable permittivity, with an array of laser engraved slits. The negative permeability then is due to a resonant confinement of the electromagnetic field within the rods. The range of negative permeability is determined by the geometry and the permittivity of the material used.