Tunable plasmonic modulator with high-modulation-depth through electrical control

We propose an electrically tunable plasmonic modulator with an Au-grating/insulator/metal sandwich structure. Current injection induces the insulating polydimethylsiloxane (PDMS) layer to expand through Joule heat, and tunes the coupled plasmonic resonances of the modulator. Simulation study review that a large wavelength tuning range of 81 nm and high modulation depth of 126% in the near-infrared region can be achieved at an injection current of 3.15 mA. The excellent modulation performance is attributed to the electrical induced PDMS tunability and strong coupling between localized surface plasmon resonance and the FP resonance, which is confirmed by the electric field distribution. The high modulation performance is promising for active optical components and integrated circuits.