Two-photon lithography of sub-wavelength metallic structures in a polymer matrix

A novel method for fabricating metallic nanostructures with sub-wavelength resolution in a polymer using simultaneous two-photon initiated reduction of a metal salt and polymerization of a negative photoresist is demonstrated. Gold nanoparticle-doped lines as narrow as 200 nm were fabricated. The dependence of line-width on laser intensity and scan speed are captured well by an analytical model. We created functional gratings and planar chiral elements, characterized their optical properties, and modeled their electromagnetic response.