Tailoring Plasmonic Properties of Metal-Dielectric Nanocomposite Thin Films

Tuning of the plasmonic properties of nanocomposite thin films made by embedding metal nanoparticles in dielectric matrices has been investigated theoretically. The working formula for localized surface plasmon resonance (LSPR) position (lambda(LSPR)) was derived to be lambda(LSPR) = lambda(p)root 1+epsilon(d) (K+f/1-f) + chi(1B) with lambda(p), epsilon(d), K, f and chi(1B) being respectively the plasma wavelength of Au, dielectric constant of matrix thin film, shape factor, volume fraction of AuNPs inside the matrix and real part of inter-band susceptibility. Using this formula, LSPR of nanocomposites can be varied by more than 300 mn the visible range. Analysis of the formula concludes that for a given volume fraction, changing shape has the maximum effect on shift in LSPR position