  The base for this manuscript was laid down by the studies carried out in the
article by Senyuk B, et. al. Proceedings of SPIE. 2005; 5936: 59360W-1-9. In
the present manuscript, a planar layer of the photosensitive cholesteric, based
on the chiral dopant 2-(4'-phenylbenzylidene)-p-menthane-3-one dissolved in the
nematic E7, under the alternating electric field was explored. In particular,
the influence of UV exposure and the value of the azimuthal anchoring energy on
electro- and photoswitching of undulation instabilities was considered. Due to
the decrease in a ratio between the LC cell thickness d and the cholesteric
helical pitch P, different types of undulations, observed under the electrical
field, were switched by UV exposure. The change in the ratio d/P was realized
owing to the unwinding of the photosensitive cholesteric helix during UV
exposure in the LC cell with a fixed thickness d. Sequential transitions of
types of the undulations from 2D to two 1D structures (1D|| and 1D_) were
achieved. The undulation structure 1D|| with a controlled period of a grating
in electric field was examined. Dependencies of jumps of the period and the
diffraction efficiency of a photosensitive cholesteric grating on the anchoring
energy of alignment layers were analyzed.
