Polarimetic Study of Atmospheric Phenomena and Its Applications

Abstract:

Polarized light occurs in three states: unpolarized, linear and circularized. Each mode of polarized light provides information about the scattering medium, from atmospheres to search for signatures of habitability. Linear polarization in the optical and near-infrared windows are optimum to study changes in cloud/hazes in planetary atmospheres. Circular polarization is important to understand the influence of multiple scattering in the atmosphere. Linear and circular polarization of comets provides information about the composition and wavelength dependence of the dust, indicative of new, active comets vs. older comets. Changes in magnetic fields (as in aurorae) can be explored with polarimetry. Atmospheric phenomena such as rainbows,clouds and haloes exhibit polarimetric signatures that can be used as diagnostics to probe the atmosphere and may be possible to extend this approach to other planets and exoplanets. Biological molecules exhibit an inherent handedness or circular polarization or chirality, assisting in search for the identification of astrobiological material in the solar system. I shall highlight observations and models for these phenomena.