Holographic gratings are recorded in photorefractive near-stoichiometric iron-doped lithium niobate crystals in the presence of an external electric field close to the coercive field of the material. The holograms are erased by homogeneous illumination. Subsequent application of an external field well above the coercive field reveals the holographic grating partly and transiently. The diffraction efficiency of the revealed grating increases for longer recording times and for larger grating period lengths. All results can be understood by a process known as electrical fixing: During recording the space-charge pattern is transferred to a pattern of ferroelectric domains.
© 2005 Optical Society of America
Helge A. Eggert, Felix Kalkum, Benedikt Hecking, and Karsten Buse, "Optimization of electrical fixing in near-stoichiometric iron-doped lithium niobate crystals," J. Opt. Soc. Am. B 22, 2553-2559 (2005)