Optical signal transmission through plasmonic waveguide under applied electrical bias

The feasibility of optical signal transmission and electrical bias separation was demonstrated by forming a 3-μm-wide separation gap between a plasmonic waveguide and a Au/Si Schottky diode. To transmit optical signals, a surface plasmon polariton was excited at the air/Au interface of the Au film deposited on the SiO₂ layer. The transmitted optical signal was detected as a photocurrent using the Au/Si Schottky diode. The electrical separation was confirmed by applying a bias voltage between the plasmonic waveguide and the Si substrate. From the transmitted power, optical signal transmission only across the electrical separation gap was confirmed.