Optical diode based on plasmonic nanosphere chains

The merging of electronics and photonics at the nanoscales overcomes the limitation in integrating photonic components into electronic chips, in which surface plasmon may play a central role in future hybrid nanocircuit integration. We report in this paper a surface plasmon optical diode based on the nonreciprocal light propagation. We show that by using a chain of plasmonic nanospheres embedded in a spatial-temporal modulated medium in silicon on insulator (SOI) waveguide the light propagates only in forward direction for metallic nanoparticles (MNPs). In this paper, the isolation of light is performed by calculating the optical intensity and propagation distance in both directions obtained by a finite difference time domain (FDTD) method. Our optical diode exhibits a large bandwidth and a competitive optical isolation region. Our design presents a fundamental feature in optical signal processing, and leverages the complementary metal-oxide semiconductor (CMOS) compatibility necessary for microelectronic industry.