Electrically induced and controlled gratings in large pitch cholesteric liquid crystals were investigated. Specially selected surface anchoring conditions together with well defined properties of cholesterics allow the formation of a stable periodic structure in the presence of a suitable external electric field. Polarization properties of first diffraction orders have been investigated as a function of the angle between the laser linear polarization and the grating direction. We propose to use two 1D gratings to create a 2D electrically controllable diffraction pattern, suitable for application in 3D optical devices.