The thermal erasure decay at different temperatures of holographic gratings thermally fixed in iron-doped lithium niobate has been exhaustively studied. An activation energy of 0.94 eV was found to be independent of the grating fringe spacing. At a given temperature the decay time is strongly dependent on the grating spacing. This dependence is well fitted to a square fringe spacing law, as predicted theoretically. From the experimental data the room-temperature hologram lifetime under illumination is extrapolated, giving as a result t(years)=(5.2±0.2)Λ<sup>2</sup> , with the grating spacing Λ in micrometers.
© 1998 Optical Society of America
L. Arizmendi, E. M. de Miguel-Sanz, and M. Carrascosa, "Lifetimes of thermally fixed holograms in LiNbO3:Fe crystals," Opt. Lett. 23, 960-962 (1998)