Synthesis and study of composite silver-polymer metamaterials

We have designed, synthesized and characterized a range of non-magnetic metamaterials with continuously tunable dielectric constant. Powders of 30 nm silver nanoparticles were suspended in Tetrahydrofuran solution of Polymethylmethacrylate and exposed to Q-switched laser radiation in order to separate nanoparticles and/or reduce the degree of aggregation. The films of Ag-PMMA composites with different concentrations of silver nanoparticles $N$ were deposited onto glass substrates and characterized in optical transmission and reflection experiments. Using known formula for reflectivity and transmissivity in three-layered structures, we extracted from the experimental data the spectra of real \textit{$\varepsilon $}$_{eff}$'\textit{($\lambda )$} and imaginary \textit{$\varepsilon $}$_{eff}$\textit{''($\lambda )$} parts of the effective dielectric constants. The experimental maximal value of \textit{$\varepsilon $}$_{eff}$' exhibited monotonous growth and reached \textit{$\varepsilon $'}=12.8 at $\lambda $=2.4 $\mu $m at the maximal concentration of Ag nanoparticles studied. The demonstrated value of \textit{$\varepsilon $}$_{eff}$' exceeds that in Si and appears to be the highest in 1.5-2.5 $\mu $m spectral range. The demonstrated easy-to-synthesize nanocomposite adds to the tool box of photonic metamaterials with extreme values of \textit{$\varepsilon $}.