Energy transfer at optical frequencies to silicon-on-insulator structures

The refractive-index distribution that is intrinsic to the silicon-on-insulator (SOI) material system makes it possible for optical-frequency guided waves to be confined by the SOI silicon layer. The same refractive-index distribution is unusual among nonmetals in that it is possible for those SOI guided waves to interact strongly with nearby optical-frequency radiators, absorbers, and scatterers (e.g., atoms, molecules, and nanoparticles). We calculate the guided-mode excitation efficiency for an exterior particle near the SOI surface and show that it can attain values greater than 80% under appropriate conditions, thus showing that the SOI waveguide system is an attractive platform for the study of optical-frequency surface interactions.