Analytical modelling of Thirty Meter Telescope polarization

Abstract

The polarization introduced due to TMT telescope optics is studied using an analytical model. Mueller matrices are also generated for each optical element using Zemax based on which the instrumental polarization due to the entire system at the focal plane is estimated and compared with the analytical model. As a fi rst step, the study is done for the on-axis fi eld treating the primary as a monolithic mirror, and the tertiary as a xed 45 degree mirror. The second step is using the actual tertiary con figuration and also extended for the full fi eld (10 arc minute). The estimation is also done at different positions of Nasmyth mirror and at various zenith angles. This study is a signi ficant aspect in the estimation of the telescope sensitivity, and also has great implications for future instruments.