Thermal optical path difference analysis of off-axis lens ray trace foot-print

The optical system lens temperature difference will cause optical aberration increase. This study is applying finite element method (FEM) and optical ray tracing; calculate off axis ray thermal optical path difference (OPD). The optical system temperature distribution is calculated from finite element simulation result and weighting temperature to each optical ray path. The simulation result shows off-axis ray major thermal optical aberrations are tilt and piston at this study.