Influence of silver-nanoparticle layer in a chiral sculptured thin film for surface-multiplasmonic sensing

Multiple surface-plasmon-polariton (SPP) waves can be guided by the interface of a metal and a chiral sculptured thin film (STF). It is possible to embed within the chiral STF a layer of silver nanoparticles as sites to bind recognition molecules for sensing analytes of a certain kind. Chiral STFs were deposited on aluminum thin films. 5-nm-thick layers of silver nanoparticles were deposited in the chiral STF at different depths in different samples. The samples were then deployed in the Turbadar–Kretschmann–Raether configuration to observe the effects the silver-nanoparticle layer had on the multiple SPP-wave modes in relation to the depth. We concluded that the silver-nanoparticle layer tends to shift the angular locations of the SPP-wave modes but does not necessarily affect the location of the SPP-wave modes to an extent that would render the data uninterpretable.