UV Polarimeters for Pollux onboard LUVOIR
Résumé
Pollux, the European high-resolution spectropolarimeter designed for LUVOIR, will work from 90 to 400 nm. In order to optimize its efficiency, the range is divided in 3 channels: far ultra-violet (FUV) from 90 to 124.5 nm, mid-UV (MUV) from 118.5 to 195 nm and near-UV (NUV) from 190 to 400 nm. Optical materials' properties being different between channels, each one will benefit from its own polarimeter adapted to its wavelength range. All polarimeters will use temporal modulation and will be composed by a modulator and an analyzer. The NUV polarimeter is similar to the one often used in in visible range: it uses waveplates and a polarizer and works thus in transmission. The FUV polarimeter has to be innovative because no birefringent material transmits light at these wavelengths. It will use mirrors and work by reflexion. The MUV polarimeter will benefit from the design of the two others so that it will be the most efficient possible. This proceeding presents these three polarimeters designed for Pollux.