Light propagation in chiral media with large pitch.

Light propagation in uniaxial chiral media with large pitch is studied. In these systems there are forbidden zones for extraordinary beams, which lead to effective reflection on zone boundaries and to wave damping inside the forbidden zone. We analyze the vicinities of the turning points and the transition of an extraordinary wave through the forbidden zone. Narrow forbidden zones with merging turning points are studied in detail. The transition through the forbidden zone is studied experimentally in nematic liquid crystal doped with a chiral addition. There is a good agreement between experimental results and theoretical calculations.