Design and analysis of inner focus for a large spectral bandwidth optical system

In this paper, we present a method of solving the chromatic aberration problem of large spectral bandwidth optical systems encountered during the internal focusing process. Rational selection of the focal length of each lens group and the distance between them retained the achromatic characteristic of the optical system when the inner focus lens group was mobilized. The proposed design was experimentally validated. This paper can be useful to research on internal focusing in wide-band systems.