Phase modulation of mixed polarization states in deformed helix ferroelectric liquid crystals

We study electro-optic properties of subwavelength-pitch deformed-helix ferroelectric liquid crystals (DHFLC) illuminated with partially polarized light. Theoretical results on the orientational Kerr effect and the modes of operation of such DHFLC cells are reviewed. By using the interferometry based approach to mixed-state geometric phases, we deduce the expressions for the total Pancharatnam and geometric phases of a partially polarized light wave passed through the DHFLC cell. We examine the effects of the polarization parameters on electric field dependence of the phases.