Linear and nonlinear optical properties of Au-polymer metallodielectric Bragg stacks

We demonstrate the fabrication of one-dimensional metallodielectric Bragg stacks (MDBSs) from 500nm spin-coated poly(methyl methacrylate) and 20nm evaporated Au layers; one-, two-, and three-bilayer structures are achieved with good homogeneity (<2% thickness variation). The linear reflection and transmission spectra show very strong modulation relative to the constituent materials for only a few bilayers; transmission windows associated with sharp Bragg resonances are observed at ∼600 and ∼850nm, while other regions provide reflections of >90%. Nonlinear absorption was measured by a z-scan technique and is observed to be enhanced at the Bragg resonances. The ∼600nm peak of the three-bilayer MDBS is enhanced by approximately seven times compared to a single Au film. The wavelength dependence of the nonlinear enhancement can be correlated with the attenuation parameter. The experimental results are in good agreement with numerical simulations based on a transfer-matrix method employing the known physical and optical parameters. The MDBSs show strong potential as versatile and inexpensive components for optical devices.