Silver nanoparticle array structures that produce giant enhancements in electromagnetic fields

We describe special silver nanoparticle array structures that lead to exceptionally large electromagnetic field enhancements (|E|2 > 107) at specific locations in the structure, thus providing a purely electromagnetic mechanism for producing single molecule surface enhanced Raman scattering (SMSERS) enhancements >1013 that are as large or larger than has been found in experiments. The arrays combine particle plasmon excitation with long range photonic interactions, leading to a combination of the two field enhancement mechanisms that not only gives large SMSERS, but also narrow peaks in extinction.