Air pocket structures for promoting total internal reflection in a waveguide

A method of manufacturing an optical system comprising:

• forming a waveguide of a high-index transparent material having front and rear sides such that the front side of the waveguide has a plurality of recesses and a plurality of raised formations, each raised formation being located between two of the recesses;
• securing a cap layer of a select transparent material to the waveguide, multiple cavities being defined between the cap layer and the waveguide with an optical gas in each respective cavity, such that, if a source of ambient light is located on the front side of the waveguide, a beam of the ambient light transmits in the select transparent material of the cap layer, in the cavities holding the optical gas and in the high-index transparent material of the waveguide;
• and
• supporting first portions of the cap layer with the raised formations with second portions of the cap layer that are located between the first portions of the cap layer being located over the recesses so that a respective one of the cavities is defined by a respective on of the second portions of the cap layer and a respective one of the recesses in the front side of the waveguide.