Cone Channel Condenser Optics*

Conical light pipes to condense radiation are attractive in their simplicity and low cost.In addition, when using detectors having non-uniform surface response, the non-image forming characteristics of such channels are desirable. Through the use of a field lens, channels may be designed which condense the radiation through a given area to the smallest possible size. As viewed from the output end of the channel, this corresponds to achievement of the optimum f/number of 0.6. Reflection losses in the experimental model described increased the f/number to 0.77. The cone channel described has the further advantage that it is not receptive to stray light.