An optical field concentrator includes a plurality of waveguide layers
comprising high index materials having a first defined thickness. At
least one nano-layer structure is positioned between said waveguide
layers. The at least one nano-layer structure comprises low index
materials having a second defined thickness that is smaller than the
first defined thickness. A plurality of cladding layers are positioned
between the waveguide layers and the at least one nano-layer structure.
The cladding layers have a third defined thickness that is larger than
the first defined thickness.