Thin lens narcissus model in infrared lens design with cooled detectors

A mathematical model of the narcissus effect in infrared lenses with cooled detectors is discussed. The proposed model enables optical designers to take the narcissus performance of infrared lenses into consideration in the thin lens predesign stage. Third order thin lens aberration theory is the basis for the newly proposed narcissus analysis. Two narcissus metrics are defined in terms of structural parameters of the infrared lens to be designed. The metrics provide an indirect way of controlling narcissus performance in thin lens predesign. A long wave infrared lens is discussed from a narcissus perspective within the proposed model as an example. It is shown that the proposed narcissus model is a very effective way of controlling narcissus performance, starting from the early stages of lens design.