In this paper we discuss about the design, construction and working of two different experimental setups to measure the depolarization ratio of natural mineral dust samples in the laboratory in the exact back-scattering direction. The first setup involves a 50:50 beam splitter and the second setup involves a Faraday rotator to achieve the 180˚ backscattering angle. Both the experimental setups will be first tested at 532 nm wavelength. Later, the setup with better results will be extended to cover the full triple-wavelength (355, 532 and 1064 nm) capabilities for linear polarization and circular polarization, enabling ellipsometry measurements of mineral dust particles.
Semwal et al. (Thu,) studied this question.