Characterization of Two-Color Holography Performance in Reduced LiNbO(3):In

The two-color recording sensitivity S and the figure of merit M/# are measured in a reduced and congruent LiNbO(3):In crystal of 2.2-mm thickness. The results are compared with those before reduction treatment. It is found that S increases by an order of magnitude through reduction treatment but the M/# is unchanged. Measured values for S and M/# in the reduced crystal are found to be 3 x 10(-3) cm/J and 0.04, respectively, with a total writing intensity of 4.0 W/cm(2) at 780 nm and a gating intensity of 1.15 W/cm(2) at 488 nm. These values are close to those of near-stoichiometric LiNbO(3) crystals under similar recording conditions. We also show that photoconductivity plays an important role in the improvement of S in LiNbO(3):In.