PNNL

Abstract

Here we describe the optical transmission response of novel coatings with subwavelength metallic structures based on a quasi-open ring resonator design fabricated via a combination of nanoimprint lithography and metal sputtering. This offers a relatively simple approach to the fabrication of dense arrays of optically responsive subwavelength structures over large areas with an oriented two-dimensional array of parallel Au nanoshells. The cross-section of the individual lines is “L” shaped with an approximately 95 nm width, 75 nm height, and pitch of 140 nm to yield a resonant optical response in the visible/near infrared spectrum. Along the long axis of the shells, the geometry is wire-like and quasi-infinite in length compared to the cross-section. This highly anisotropic structure has a strongly polarization-dependent optical response. The coatings are characterized via optical transmission measurements as a function of wavelength, polarization, and angle are presented along with complementary numerical modeling results predicting the resonance shift with corresponding changes in fabrication parameters.