Optical combiner apparatus

An optical combiner comprising

• an optically transparent substrate comprising a volume of optically transparent material defined by a front face, a rear face opposite the front face, a first end, a second end opposite the first end, and a wave propagation axis extending along a length of the volume from the first end to the second end;
• and
• a patterned region included within the volume of the optically transparent substrate;
• wherein the patterned region comprises optically transparent regions and optically reflective regions;
• and
• wherein the optically reflective regions comprise reflective dots that are distributed throughout a portion of the volume in a first direction parallel to the wave propagation axis and a second direction perpendicular to the wave propagation axis, wherein the reflective dots are inclined at an angle relative to the wave propagation axis and spaced apart from one another in the first direction and the second direction, and wherein the reflective dots reflect rays emitted from the first end or the second end through the front face.