Study of developing thermal fixed holograms in lithium niobate

Experimental results on the developing kinetics and final diffraction effic iency of fixed holograms in iron-doped lithium niobate are presented. Sampl es with two different oxidation states are studied. The developing kinetics of well-oxidized samples show oscillations superposed to a saturation depe ndence, whereas they are not present for the less oxidized sample. The fina l developed ratio is found to depend on the grating spacing and the oxidati on state of the samples. All these features are well explained with the cha rge-transport theory and are found to be dependent on the photovoltaic prop erties of the samples, doping, and oxidation state. From the analysis of th e experimental data, the photovoltaic field amplitude of the samples is obt ained. (C) 2000 Optical Society of America [S0740-3224(00)00207-1].