Near-Field Optical Properties of AgxAu1−x Nanoparticle Chains Embedded in a Dielectric Matrix

摘要: We study by the finite-difference time-domain method near-field optical properties of isolated or coupled Ag x Au1−x alloy nanoparticles shallowly buried inside dielectric matrices. The index alloys is obtained experimentally using spectroscopic ellipsometry measurements from multilayered thin films fabricated ion-beam sputtering. Then, we numerically investigate influence nanoparticle composition, interparticle gap and capping-layer thickness on amplitude spatial extent electric field in vicinity ellipsoidal nanoparticles. Our calculations provide evidence that pure metal (Ag Au) exhibit a greater enhancement associated with larger out-of-plane compared to nanoparticles, an effect even more pronounced when surrounding matrix increased. Moreover, show optimal between maximize at capping layer/air interface results delicate balance, which strongly depends layer.