Optical Systems with Gratings and Anti-reflective Layers

A display system comprising:

• a waveguide configured to propagate image light;
• and
• a surface relief grating structure at the waveguide, wherein the surface relief grating structure comprises:
• a plurality of ridges separated by a plurality of troughs;
• and
• an anti-reflective layer formed between the waveguide and the plurality of ridges.

A display system comprising:

• a waveguide configured to propagate image light, wherein the waveguide has first and second opposing sides;
• and
• at least one surface relief grating structure at the waveguide, wherein the at least one surface relief grating structure comprises:
• a plurality of ridges separated by a plurality of troughs, wherein the plurality of ridges is formed on the first side of the waveguide;
• a first anti-reflective layer formed on the first side of the waveguide and aligned with a first subset of the plurality of ridges;
• and.
• a second anti-reflective layer formed on the first side of the waveguide and aligned with a second subset of the plurality of ridges, wherein the first anti-reflective layer has at least one property that is different than in the second anti-reflective layer.