Modeling of optical aberrations due to thermal deformation using finite element analysis and ray-tracing

Thermo-optical simulation is an important extension of classical ray-tracing because many applications, especially in laser technology, have to deal with thermal effects. This paper discusses an approach for modeling thermally induced surface deformations of rotational symmetric optical systems: the discrete deformation data generated by Finite Element Analysis (FEA) are approximated using a global even polynomial which is then transferred to the ray-tracing. The implemented algorithm is validated by comparing approximated data to an analytic deformation function. Finally, the benefit of modeling the temperature dependent refractive index and the thermal deformation is demonstrated using the example of a plastic lens.