Detection and characterization of attenuated multimode waveguiding in SiO2 slabs using photoemission electron microscopy

Multimode waveguiding in the visible and near-ultraviolet spectral regime is observed and characterized in thermally grown SiO2 layers on silicon using photoemission electron microscopy (PEEM). Comparison with finite-element-method simulations allows identifying order and character of the attenuated modes. Real-time investigations on mode propagation support these findings and give additional evidence for the existence of radiative modes. Finally, the presented experimental results illustrate how a defined deposition of gold nanoparticles can substantially enhance the sensitivity of the PEEM technique to electromagnetic field modes supported by thin dielectric and insulating layers.