title: Ultra-broadband wide-angle unidirectional plasmonic coupler based on joint effects of plasmonic critical angles and subwavelength metallic gratings.
abstract: A unidirectional plasmonic coupler with ultra-broadband and wide-angle coupling efficiency is proposed and demonstrated. Employing the plasmonic critical angle (PCA) phenomenon in conjunction with the effect of subwavelength metallic gratings, a wide incident angular full-width-half-maximum (AFWHM >28°) coupling efficiency larger than 50% and extinction ratio better than 15 dB over an ultrabroad wavelength range 725-985 nm (bandwidth >260  nm) are achieved. The operation principle and performance of the structure are clarified and theoretically illustrated.
authors.forename: Fan
authors.initials: F
authors.lastname: Lu
authors.forename: Feng
authors.initials: F
authors.lastname: Xiao
authors.forename: Kun
authors.initials: K
authors.lastname: Li
authors.forename: Anshi
authors.initials: A
authors.lastname: Xu
mesh_terms: D004867:Equipment Design; D008027:Light; D055096:Optical Devices; D055620:Optical Phenomena; D012031:Refractometry / Q000295:instrumentation* / Q000706:statistics & numerical data; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000706:statistics & numerical data