title: Circular dichroism in the optical second-harmonic emission of curved gold metal nanowires.
abstract: Here we report the experimental observation of circular dichroism in the second-harmonic field (800-400 nm conversion) generated by self-organized gold nanowire arrays with subwavelength periodicity (160 nm). Such circular dichroism, raised by a nonlinear optical extrinsic chirality, is the evident signature of the sample morphology. It arises from the curvature of the self-assembled wires, producing a lack of symmetry at oblique incidence. The results were compared, both in the optical linear and nonlinear regime, with a reference sample composed of straight wires. Despite the weak extrinsic optical chirality of our samples (not observable by our optical linear measurements), high visibility (more than 50%) was obtained in the second-harmonic generated field.
authors.affiliation: Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza Università di Roma and CNISM, Via A. Scarpa 16, I-00161 Roma, Italy. alessandro.belardini@uniroma1.it
authors.forename: A
authors.initials: A
authors.lastname: Belardini
authors.forename: M C
authors.initials: MC
authors.lastname: Larciprete
authors.forename: M
authors.initials: M
authors.lastname: Centini
authors.forename: E
authors.initials: E
authors.lastname: Fazio
authors.forename: C
authors.initials: C
authors.lastname: Sibilia
authors.forename: D
authors.initials: D
authors.lastname: Chiappe
authors.forename: C
authors.initials: C
authors.lastname: Martella
authors.forename: A
authors.initials: A
authors.lastname: Toma
authors.forename: M
authors.initials: M
authors.lastname: Giordano
authors.forename: F
authors.initials: F
authors.lastname: Buatier de Mongeot
mesh_terms: D002942:Circular Dichroism; D006046:Gold / Q000737:chemistry*; D008422:Materials Testing; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D013499:Surface Properties
chemical_list: D006046:Gold