title: Concentrating evanescent waves: systematic analyses of properties of the needle beam in three-medium dielectric cylindrical waveguide.
abstract: Needle beam is a guided beam with nanoscale beam size and significant power propagating in core area of a three-layer dielectric waveguide. Systematical numerical analyses of properties of the needle beam are presented. Properties of the fundamental mode of the needle beam, including field distribution, power distribution, and power concentration, are calculated for different waveguide parameters. It is shown that there is an optimum value of normalized frequency for maximum power concentration. Concentrated power is higher if the refractive index difference between the core and the middle layer is higher.
authors: Department of Physics, College of Science, China University of Petroleum, Beijing Campus, 18 Fuxue Road, Changping, Beijing, 102249, China.
authors: Fangli
authors: F
authors: Qin
authors: Yang
authors: Y
authors: Zhao
mesh_terms: D000465:Algorithms; D008027:Light; D008422:Materials Testing; D008962:Models, Theoretical; D055100:Optical Fibers; D012031:Refractometry / Q000379:methods*; D013057:Spectrum Analysis / Q000379:methods*