Abstract: An optical device includes a substrate, a first surface-relief grating including grooves and ridges formed on or in the substrate, a first overcoat layer in the grooves of the first surface-relief grating, and a first antireflective layer on the first overcoat layer. The ridges of the first surface-relief grating include high-refractive index, photoactive metal oxide nanoparticles and a material of the first overcoat layer in regions between the metal oxide nanoparticles, or the first overcoat layer includes the metal oxide nanoparticles and a material of the first antireflective layer in regions between the metal oxide nanoparticles. Methods of fabricating the optical device are also described.

Abstract: An optical device includes a substrate, a surface-relief grating including grooves and ridges formed on or in the substrate, and an overcoat layer in the grooves of the surface-relief grating. The ridges of the surface-relief grating or the overcoat layer includes a plurality of clusters of metal oxide (e.g., TiO2 or NbOx) nanoparticles. Each cluster of the plurality of clusters of metal oxide nanoparticles includes metal oxide nanoparticles dispersed in an inorganic barrier that isolates the metal oxide nanoparticles from other materials of the optical device. The ridges of the surface-relief grating or the overcoat layer is made of a resin material that includes a resin with inorganic content, and/or TiOx or NbOx nanoparticles including inorganic-containing ligands. A high-energy treatment process can remove organics surrounding the metal oxide nanoparticles and form the barrier layers that surround clusters of metal oxide nanoparticles.

Abstract: A formulation for inkjet printing includes one or more solvents and a plurality of nanoparticles mixed with the one or more solvents. The plurality of nanoparticles has a first refractive index greater than 1.9. A method includes depositing a layer of the formulation by inkjet printing onto a substrate having a non-flat. The method thereby forms coating of the formulation having a first surface conforming to the non-flat surface of the substrate and a second surface, opposite to the first surface, being a flat surface. An optical device includes a surface relief grating and a coating layer disposed on the surface relief grating. The coating layer includes a plurality of nanoparticles having a refractive index greater than 1.45 and a resin. The plurality of nanoparticles has functional ligands cross-linked with the resin.