The Pockels effect can be used to tune the effective birefringence of ambichiral structures made of electro-optic
materials with 42<i>m</i> point group symmetry, when a dc electric field is applied parallel to the axis of
nonhomogeneity. The reflectances and transmittances of such an ambichiral structure can be calculated through
the solution of a boundary-value problem. The Bragg resonance peaks, for different circular-polarized-incidence
conditions, blueshift as the angle of incidence increases.