All-optical logic binary encoder based on asymmetric plasmonic nanogrooves

We report an all-optical logic binary encoder based on two asymmetric plasmonic nanogrooves etched in a gold film coated a polyvinyl alcohol layer. The physical mechanism originates from the unique capability of plasmonic nanogrooves in modulating the propagation properties of surface plasmon polaritons. The incident signal lights dropping in different wavelength regions are endowed with different logic state encodings. In such an ultracompact device with a feature size of only 2.4 μm, the coupling of free-space signal lights to surface plasmon polaritons and the on-chip encoding are integrated together, which is much suitable for practical integration applications.