Actively bias-controlled metamaterial to mimic and modulate electromagnetically induced transparency

We present an active microwave metamaterial composed of orthogonally arranged cut wires and positive-intrinsic-negative diodes, having capability of high-speed response. When a forward voltage is applied to turn the diodes on, analogue spectral response of a classical electromagnetically induced transparency is observed at 6.13 GHz for destructive interference between dipolar and quadrupolar resonances in the cut wires. Besides, experiments demonstrate that around the frequency, response amplitude is modulated continuously by sweeping the bias, and intensity modulation depth is up to 85%. Surface current distributions verify that the diode conductivity decides coupling efficiency of the resonant fields and consequent the amplitude. Simulated and measured spectra are in good agreement.