L. Gonzalez-García , J. Parra-Barranco , J.R. Sanchez-Valencia , J. Ferrer , M.C. Garcia-Gutierrez, A. Barranco, A.R. Gonzalez-Elipe
Advanced Functional Materials, 23 (2013) 1655-1663
doi: 10.1002/adfm.201201900

A simple method is presented to tune the gold surface plasmon resonance (SPR) modes by growing anisotropic nanoparticles into transparent SiO₂ thin films prepared by glancing angle deposition. In this type of composite film, the anisotropy of the gold nanoparticles, proved by gracing incidence small angle X-ray scattering, is determined by the tilted nanocolumnar structure of the SiO₂ host and yields a strong film dichroism evidenced by a change from an intense colored to a nearly transparent aspect depending on light polarization and/or sample orientation. The formation in these films of lithographic non-dichroic SPR patterns by nanosecond laser writing demonstrates the potentialities of this procedure to develop novel optical encryption or anti-counterfeiting structures either at micrometer- or macroscales.