Optically tunable plasmon-induced transparency in terahertz metamaterial system

An optically tunable terahertz modulator based on plasmon-induced transparency (PIT) metasurface was investigated theoretically and experimentally. It was found that, upon near infrared photoexcitation, the resonance degree of the transparent window displayed a decreasing tendency and emerged a weaker blue-shift phenomenon. And when the optical pump power was tuned to 1000 mW, the resonant transmission modulation depth reached to 81.68% at 0.81 THz. Furthermore, a coupled Lorentz oscillator model was adopted to analyze the near field interaction of the resonances. •Optically tunable terahertz modulator based on plasmon-induced transparency.•Large numbers of carriers were excited in the p-type Silicon.•The resonances transmission of the PIT metamaterial was optically modulated.•Coupling coefficient between the resonators decreased owing to screening effect.