Chirality is an excellent indicator of life, but naturally occurring astrobiological (as well as terrestrial) samples nearly always exhibit massive depolarizing light scattering, which renders conventional polarimeters useless. For astrobiological applications, we instead consider a novel polarimeter originally developed for non-invasive human-glucose measurement. It involves deliberately rotating in time the plane of polarization of a linearly polarized beam and detecting the shift in the plane of the rotating linearly polarized component of the transmitted light from a chiral sample relative to the input polarization plane. We find that this polarimeter can operate in 3 orders of magnitude more depolarizing scattering than conventional polarimeters. Furthermore, it can also be designed to be lightweight, compact, and energy efficient.
Astrobiology. December 2008, 8(6): 1061-1069.