Schematics of a single waveguide system with dual-mode embedded metagrating solution illustrating angles of incident and diffracted light for reflective and transmissive diffraction gratings for three different colors: (a) blue, (b) green, (c) red. Angles denoted using θ are located in the air. Angles denoted using Φ are located in the waveguides and measure the angle of rays that have been diffracted. Superscript C indicates a critical ray (just at the TIR limit in the waveguide), either in air or in the waveguide. Superscript G indicates a grazing ray (the highest allowed angle of incidence in the waveguide).