<title>Intrinsic optical bistability of structured nanoparticle composites</title>

Abstract

We report here intrinsic optical bistability calculations for structured nanoparticle composites, ie. particles consisting of one or more coatings of different materials. The bistability is based on the nonlinear field dependence of the plasmon resonance introduced through the nonlinear component. The single shell structured nanosphere model consists of a nonlinear organic or semiconductor core with a metallic shell; and the two shell model has a metallic core, nonlinear dielectric shell and metallic second shell. The metals examined are Ag or Osmium, the nonlinear dielectrics are PDA, Si, GaAs, InSb and the host medium is water or a glass. Calculations show that the switching power level for intrinsic bistability can be reduced in the one spherical shell nanosphere composite to less than 1 MW/cm2 with no loss in the speed of response. In the two shell model, power levels for onset of bistability can be 1 kW/cm2. CdS with a silver coating has a threshold of 12 W/cm2, when an ellipsoidal shaped particle is used.