Ray Traces through Hollow Metal Light-Pipe Elements

Abstract

Rays have been traced through hollow straight light pipes, condensing cones, mitered right angles, and toroidal right-angle bends. The results presented include transmittance and average number of reflections in representative elements. Condensing cones should be kept short to minimize reflection losses, and mitered corners are superior even to ideal bends in all cases of practical interest. A formula is derived for the average number of reflections for all rays’skew and meridional’in a straight pipe. The discussion is limited to elements of circular cross section, and the emphasis is on applications to the far infrared.