Optical devices including metastructures and methods for fabricating the optical devices

A method of manufacturing an optical device comprising:

• providing a substrate having a first polymeric layer over a surface of the substrate and a second polymeric layer on the first polymeric layer;
• forming first openings in the second polymeric layer to define an etch mask composed of material of the second polymeric layer;
• etching to form second openings in the first polymeric layer, wherein locations of the second openings are defined by the etch mask, wherein etching to form the second openings comprises leaving a residual thin film of the first polymeric layer in the second openings;
• and
• depositing a material in the second openings to fill the second openings with meta-atoms of a first metastructure, wherein adjacent ones of the meta-atoms are separated from one another by polymeric material of the first polymeric layer, wherein the meta-atoms of the first metastructure are an oxide, a nitride or a metal.