  Electromagnetically induced transparency (EIT) is a promising technology for
the enhancement of light-matter interactions, and recent demonstrations of the
quantum EIT realized in artificial micro-structured medium have remarkably
reduced the extreme requirement for experimental observation of EIT spectrum.
In this paper, we propose to electrically control the EIT spectrum in a
metamaterial for an electromagnetic modulator. A diode acting as a tunable
resistor is loaded in the gap of two paired wires to inductively tune the
magnetic resonance, which induces remarkable modulation on the EIT spectrum
through the metamaterial sample. The experimental measurements confirmed that
the prediction of electromagnetic modulation in three narrow bands on the EIT
spectrum, and a modulation contrast of up to 31 dB was achieved on the
transmission through the metamaterial. Our results may facilitate the study on
active/dynamical technology in translational metamaterials, which connect
extraordinary manipulations on the flow of light in metamaterials, e.g., the
exotic EIT, and practical applications in industry.
