Resonance switching using ultrafast laser in THz plasmonic devices based on hybrid structure of semiconductor and carbon nanotube

We demonstrate all-optical switching of plasmonic resonance patterned on the carbon nanotube films supported on the silicon substrates. A considerable suppression of terahertz wave was observed in the transmission resonance, when the near-infrared femtosecond laser pulse is irradiated. A Fourier-transformed terahertz spectrum reveals that the resonance feature that was governed by the geometry of the slot antenna are almost completely removed with the laser irradiation having sufficiently high pulse energy reaching 18 μJ. A screening of terahertz field was analyzed in terms of the free carrier generation originating from the photoexcitation in semiconductor film.