Low-power and ultrafast all-optical tunable plasmon-induced transparency in plasmonic nanostructures

We report an ultrafast and low-power all-optical tunable plasmon-induced transparency in a plasmonic nanostructure consisting of a gold nanowire grating embedded in a polycrystalline lithium niobate layer, realized based on strong quantum confinement enhancing nonlinearity. The all-optical tunability is realized based on the third-order nonlinear Kerr effect. A shift of 30 nm in the central wavelength of the transparency window is achieved under excitation of a pump light with an intensity as low as 7 MW/cm². An ultrafast response time of 69 ps is reached because of ultrafast relaxation dynamics of bound electrons in polycrystalline lithium niobate.