We proposed a ferroelectric domain controlled graphene based surface plasmon polariton modulator. Ferroelectricity-induced electronic and optical property tuning of graphene by domain in lithium niobate was theoretically investigated considering both interband and intraband contributions of surface conductivity. With the corrected Sellmeier equation of lithium niobate, the propagation of transverse magnetic mode surface plasmon polaritons in an air/graphene/lithium niobate structure was studied when monolayer graphene was tuned by down polarization direction ferroelectric domain with different polarization levels. The length of the ferroelectric domain was optimized to be 90 nm for a wavelength of 5.0 μm with signal extinction per unit 14.7 dB/μm, modulation depth 474.1 dB/μm and figure of merit 32.5. This work may promote the study of highly efficient modulators and other ultra-compact nonvolatile electronic and photonic devices in which two-dimensional materials and ferroelectric materials are combined.

A polarization-sensitive V-shaped slot nanoantenna column is utilized to realize tunable unidirectional coupling of surface plasmon polaritons (SPP). Two plasmon resonant modes are excited in the V-shaped slot nanoantennas with xand y-polarized incident light, respectively. The electric fields of coupled SPP show different symmetries corresponding to that of the two resonant modes. Linear combinations of the two resonant modes result in asymmetric SPP intensity distributions. As a result, by controlling the incident polarizations, tunable unidirectional coupling of SPP to two opposite directions perpendicular to the column at different wavelengths are realized. A highest extinction ratio of 36.7 dB is achieved, and the extinction ratio keeps larger than 7 dB within a wavelength of 149 nm.

A method to detect the full Stokes parameters utilizing a double-ring and Archimedes-curves distributed nanoslits plasmonic lenses is proposed. We demonstrate theoretically and numerically that both of these two plasmonic lenses can focus surface plasmon polaritons to centrally symmetric fields with subwavelength-sized focal spots under linear, elliptical, and circular polarization incidence. The intensity at the focal spots is modulated by the polarization state of incident light. Utilizing this intensity polarization sensitivity, the full Stokes parameters of incident light are detected by recoding only four intensities at the focal spots of these two plasmonic lenses.