Plasmonic Polarization‐Rotating Emitters with Metallic Nanogroove Antennas

Abstract A subwavelength plasmonic polarization‐rotating emitter is numerically and experimentally demonstrated by designing a metallic nanogroove antenna on the metal surface. The numerical simulation shows that there is a strong resonance in the nanogroove antenna when a surface plasmon polariton mode impinges it, and the polarization of the free‐radiation field emitted by the nanogroove antenna is mainly perpendicular to the long side of the nanogroove antenna. As a result, the polarization of the free‐radiation field can be easily rotated by tilting the nanogroove antenna. Experimentally, the metallic nanogroove antennas are fabricated, and the polarization‐rotating emitters are demonstrated. By tilting the nanogroove antenna with an angle of θ (<60°), the polarization of the free‐radiation field can be rotated by θ, and the linear polarization is nearly preserved in a broad bandwidth of Δλ = 180 nm. Because of the polarization rotation of the plasmonic emitter, it is demonstrated that the signal–noise ratio of the far‐field collection can be greatly improved. This subwavelength (0.07λ²) and broadband (Δλ = 180 nm) plasmonic polarization‐rotating emitter based on the nanogroove antenna provides a new degree of freedom to tailor the light emission from the confined waveguide modes on chips, and it may find important applications in the interchip optical communications.