title: Near-field beam focusing by a single bare subwavelength metal slit with the high-index transmission space.
abstract: We theoretically demonstrate that a single bare subwavelength metal slit without any surrounding corrugations can have a capability to steer the incident light into focusing patterns by introducing a high index in the transmission half-space. The focusing properties are identified to depend on both the slit width and the output permittivity. The underlying physics lies in the interference of quasi-cylindrical waves scattered from the slit, and our proposed model agrees well with the simulation results. This finding is believed to inspire some novel ideas for the nano-optics design.
authors.affiliation: Institute of Modern Optics, Nankai University, Key Laboratory of Optical Information Science and Technology, Education Ministry of China, Tianjin, 300071, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Guo
authors.forename: Bo
authors.initials: B
authors.lastname: Zhao
authors.forename: Jianjun
authors.initials: J
authors.lastname: Yang
mesh_terms: D003198:Computer Simulation; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry*; D008962:Models, Theoretical; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation