OPTICAL DEVICES INCLUDING AN OPTICAL LAYER ON A SUBSTRATE

An optical device includes a substrate and an optical layer disposed on the substrate. In some implementations, a surface of the substrate that forms an interface with the optical layer is non-planar, and an overall surface area of the interface is greater than if the surface of the substrate were planar. Adhesion of the optical layer to the substrate can, at least in some cases, be improved by the higher surface area of the interface.