Giant field enhancement in resonant all-dielectric multi-layers: Advantages and limitations

All-dielectric multilayer structures are emerging as optical components of great utility for experiments in which strong but localized fields are needed. These structures allow for an incoming field to resonantly interact with the layers in such a way as to create a giant field at the surface of the structure, where sensing, imaging, and other applications can take place. We present how we synthesize such structures to achieve optical responses with orders of magnitude field enhancements. Furthermore, we introduce and optimization method to achieve enhancements up to 10⁴. We will then present the advantages and drawbacks, and discuss the impact of the illumination bandwidths (angular divergence and spectral range). Subsequently, we will estimate the fabrication errors (in thicknesses and refractive index) over the optical response of the all-dielectric component and especially the field enhancement at the free interface. We will finally give a brief comparison with the surface plasmon resonances to evidence the assets and drawbacks for each case in the context of sensing applications.