Theory of electrically controlled exhibition of circular Bragg   phenomenon by an obliquely excited structurally chiral material. Part 2:   arbitrary dc electric field
  Numerical examination of the solution of the boundary--value problem of the reflection and transmission of a plane wave due to a slab of an electro--optic structurally chiral material (SCM) indicates that the exhibition of the circular Bragg phenomenon by the SCM can be controlled not only by the sign and the magnitude of a dc electric field but also by its orientation in relation to axis of helicoidal nonhomogeneity of the SCM. Thereby, the possibility of electrical control of circular--polarization filters has been extended. 
A. Lakhtakia, J.A. Reyes