Design Aspects of Stokes Polarimeter for Solar Observations

Abstract

Measurement of line polarization is an essential step towards remote sensing of the solar magnetic fields. The instrument used for measuring the polarization is known as polarimeter. Waveplate is one of the main parts of the polarimeter. Before using this element it is necessary to characterize it for different required wavelengths because this component is highly dependent on the wavelength of light. In the first phase of the project the available Pancharatnam half-waveplate was characterized for different wavelength range of light and the measured retardation values were used to simulate the efficiency of the dual beam spectropolarimeter (Nagaraju et al., 2007). The dual beam spectropolarimeter is designed for l = 630nmand eight stage modulation scheme is used for this polarimeter. In the second phase of the project, different types of modulations schemes for polarimeter design was studied in the wavelength range of 400nm to 700nm.