Polarimeter with a high-speed rotating waveplate for the solar observation

We developed a polarimeter for the ground-based solar observation using a high-speed rotating waveplate (typically 12.5–25 revolutions s−1) and a high-speed camera (typically 200–400 frames s−1) with commercially available devices. Fast polarization modulation is required for the ground-based solar polarimetry to avoid producing seeing-induced false polarization signals. Modulation with a high-speed rotating waveplate realizes not only fast full-Stokes modulation but also wide coverage of the wavelength range, and therefore, a polarimeter with a highspeed rotating waveplate is most suitable for the simultaneous polarimetry observations at multi-wavelengths with a spectrograph. A comprehensive description of the instrument and some results of the solar spectropolarimetry with this polarimeter are given in this paper.