Determination of polarimetric capabilities of the Thirty Meter Telescope

The polarization model for one of the future generation telescope, the Thirty Meter Telescope (TMT) will be presented. The polarization ray tracing model gives the complete Mueller matrices of all the mirrors of the telescope. The instrumental polarization and crosstalk are found to be varying significantly with the field of view of the telescope, zenith angle, and the position of the instrument ports due to the inclined tertiary mirror of the telescope. We also propose a design to mitigate the effect of polarization arising from the Nasmyth mirror by using an inclined mirror kept orthogonal to it. The polarization aberrations arising due to the non-normal incidences and coating has been calculated to ascertain its effect on the point spread function of the telescope. The effects of the segments and coating non-uniformities have been studied. These analysis will be useful for the design of the future polarimetric instruments for TMT.