Design of a tessar lens including a diffractive optical element

To study the quantitative impact of diffractive optical elements on lens design and glass selection, a Zeiss Tessar lens (f/6) with and without a diffractive optical element is optimized with respect to the wavefront performance by a Zemax(R) Hammer routine. Optimization includes the selection of glasses as well as the geometry of the optical elements. In a first run, these are all refractive elements. In a second run, one refractive element is replaced with one diffractive surface. In a third run, the diffractive surface is introduced as an additional feature. It is found that one refractive element can be replaced with a diffractive surface at a moderate loss of lens performance. This holds, however, only for an optimized glass selection, which is found to be particularly important. In the case of four refractive elements plus diffractive surface, an according result is obtained. The diffractive surface will improve the overall system performance if and only if the glass selection is appropriate.