Stigmatic and coma-free imaging with a thick prism: a comparison of third-order theory and ray-tracing results

Although the use of prisms is often avoided because of their aberrations, they are suitable for image-tilt correction. In contradiction to current recommendations, zero astigmatism together with zero coma cannot be achieved at minimum deviation. This paper describes two configurations that meet these conditions. A correction of earlier published third-order formulas is presented and compared to ray-tracing results. The results of the third-order theory are used to develop a model for image-tilt correction, while introducing minimal coma and maintaining a flat image field.