Concept of a Wavelength Tunable Solar Polarimetry

Wavelength tunability of a typical solar polarimetry is limited to its design wavelength and very close to that. Any change in the wavelength will drastically reduce the efficiency of the polarization measurement. A new design for a polarization modulator has been studied and is found to be tunable for a large wavelength range. The design involves three zero-order polymer retarder and combinining them suitably. The basic principle of the design is similar to that of the well-known Pancharatnam technique for an achromatic waveplate design. A theoretical understanding of this tunable modulator design will be presented. The wavelength tunability of this design will be compared with other modulator preformances.