Concentrating photovoltaic (CPV) systems and their optical
materials have come from a wide background of similar optical
reduction technologies. For example, they can be closely related
to the field of optical lithography [1], which relies greatly on
reduction optics of liquids for precise nanoscale patterning. This
carries over to the primary optics (those used with 1 sun
irradiance) and the secondary optics (those used at multiple sun
irradiances) in a CPV system. According to Swanson [2], CPV