Optical assessment of nonimaging concentrators

An optical measurement method for nonimaging radiation concentrators is proposed. A Lambertian Light source is placed in the exit aperture of the concentrator. Looking into the concentrator's entrance aperture from a remote position, one can photograph the transmission patterns. The patterns show the transmission of radiation through the concentrator with the full resolution of the four-dimensional phase space of geometric optics. By matching ray-tracing simulations to the measurement, one can achieve detailed and accurate information about the geometry of the concentrator. This is a remote, noncontact measurement and can be performed in situ for installed concentrators. Additional information regarding small-scale reflector waviness and surface reflectivity can also be obtained from the same measurement with additional analysis. (C) 2000 Optical Society of America. OCIS codes: 000.4430, 080.2740, 120.7000, 120.4290.