Design and construction of a short-wave infrared 3.3X continuous zoom lens

We present the definition, design, and construction of a 3.3X continuous-zoom short-wave infrared (SWIR) telephoto lens. Compared to visible and mid-wave infrared lenses, defining the appropriate lens requirements of short-wave lenses have some different trade-offs in terms of balancing radiometry and optimum focal plane sampling. In addition, the design process of optimizing a visible zoom design form of given first-order properties to work in the SWIR band reveals some challenges in glass selection and subsequent aberration balancing. A comparison of the actual measured MTF performance of a prototype lens shows reasonable performance compared to the design.