title: Experimental verification of the rainbow trapping effect in adiabatic plasmonic gratings.
abstract: We report the experimental observation of a trapped rainbow in adiabatically graded metallic gratings, designed to validate theoretical predictions for this unique plasmonic structure. One-dimensional graded nanogratings were fabricated and their surface dispersion properties tailored by varying the grating groove depth, whose dimensions were confirmed by atomic force microscopy. Tunable plasmonic bandgaps were observed experimentally, and direct optical measurements on graded grating structures show that light of different wavelengths in the 500-700-nm region is "trapped" at different positions along the grating, consistent with computer simulations, thus verifying the "rainbow" trapping effect.
authors.affiliation: Center for Optical Technologies, Electrical and Computer Engineering Department, Lehigh University, Bethlehem, PA 18015, USA. qqgan@buffalo.edu
authors.forename: Qiaoqiang
authors.initials: Q
authors.lastname: Gan
authors.forename: Yongkang
authors.initials: Y
authors.lastname: Gao
authors.forename: Kyle
authors.initials: K
authors.lastname: Wagner
authors.forename: Dmitri
authors.initials: D
authors.lastname: Vezenov
authors.forename: Yujie J
authors.initials: YJ
authors.lastname: Ding
authors.forename: Filbert J
authors.initials: FJ
authors.lastname: Bartoli
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D008027:Light; D018625:Microscopy, Atomic Force; D049329:Nanostructures; D012031:Refractometry / Q000295:instrumentation / Q000379:methods; D013499:Surface Properties