A compound figure of merit for photonic applications of metal nanocomposites

Selecting nanocomposites for photonic switching applications requires optimizing their thermal, nonlinear and two-photon absorption characteristics. We simplify this step by defining a compound figure of merit (FOM_{C}) for nanocomposites of noble metals in dielectric based on criteria that limit these structures in photonic applications, i.e. thermal heating and two-photon absorption. The device independent results predict extremely large values of FOM_{C} for a specific combination of the metal and insulator dielectric constant given by \epsilon_{h}=\frac{\epsilon_{1}-\epsilon_{2}}{2}, where \epsilon_{h} is the dielectric constant of the host and \epsilon_{1} and \epsilon_{2} are the real and imaginary parts for the metal.