A structure for an electro-optically controlled liquid crystal diffraction grating is proposed, which can dramatically simplify the fabrication process of liquid crystal optical gratings. The structure consists of two alternating stripes. Each stripe is a hybrid liquid crystal cell with adjacent stripes oriented perpendicularly. This kind of electro-optically controlled diffraction grating in principle gives 100% diffraction efficiency and no polarization direction dependence. The detailed fabrication process is presented.

The effect of Er[Formula: see text] ion concentration and incoherent pumping field on the Fraunhofer diffraction pattern of the transmitted light beam in Er[Formula: see text]: YAG crystal is discussed. It is shown that under different concentration of Er[Formula: see text] ion in crystal, the energy of the probe light can transfer to the higher orders of the grating. Also, it is shown that the switching from electromagnetically induced grating to electromagnetically induced phase gratin or vice versa can be obtained by different concentration of Er[Formula: see text] ion and incoherent pumping rate in crystal. Moreover, we have found that by replacing the probe light by optical vortex light, the asymmetric diffraction pattern can be obtained by tuning the optical vorticity of optical vortex light. In this case, the asymmetric diffraction pattern can also be controlled at different ion concentration.

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