2D polymer/metal structures for surface plasmon resonance

In this paper, we present a new type of polymer/metal structures for surface plasmon resonance (SPR) applications. The polymer structures with different periods were fabricated by a single-step 3D laser lithography using direct laser writing process based on non-linear two-photon absorption. Prepared polymer structures were coated by a thin film of gold. The morphological properties of final SPR structures were analyzed using a scanning electron microscope and atomic force microscope. The reflection spectra of the SPR structure with a defined period were simulated using a finite-difference time-domain method. The prepared structures show a sharp spectral dip due to the SPR effect in reflection measurements in a visible spectral range. The effect of SPR was also investigated in the angular dependence and confirmed the strong effect of 2D grating on SPR dip formation.