title: Influence of film thickness on the optical transmission through subwavelength single slits in metallic thin films.
abstract: Silver and gold films with thicknesses in the range of 120-450 nm were evaporated onto glass substrates. A sequence of slits with widths varying between 70 and 270 nm was milled in the films using a focused gallium ion beam. We have undertaken high-resolution measurements of the optical transmission through the single slits with 488.0 nm (for Ag) and 632.8 nm (for Au) laser sources aligned to the optical axis of a microscope. Based on the present experimental results, it was possible to observe that (1) the slit transmission is notably affected by the film thickness, which presents a damped oscillatory behavior as the thickness is augmented, and (2) the transmission increases linearly with increasing slit width for a fixed film thickness.
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos 13560-970, SP, Brazil. ferri@ursa.ifsc.usp.br
authors.forename: Fabio A
authors.initials: FA
authors.lastname: Ferri
authors.forename: Victor A G
authors.initials: VA
authors.lastname: Rivera
authors.forename: Sérgio P A
authors.initials: SP
authors.lastname: Osorio
authors.forename: Otávio B
authors.initials: OB
authors.lastname: Silva
authors.forename: Antonio R
authors.initials: AR
authors.lastname: Zanatta
authors.forename: Ben-Hur V
authors.initials: BH
authors.lastname: Borges
authors.forename: John
authors.initials: J
authors.lastname: Weiner
authors.forename: Euclydes
authors.initials: E
authors.lastname: Marega