Stability of fixed holograms in LiNbO3

The stability of fixed volume phase holograms in lithium niobate is studied. The new measurement method is able to distinguish between electronic compensation and true erasure. It is found that at temperatures in the range of 70-120 degrees C both electronic thermal detrapping and ionic movement are active effects. The actual lifetime of fixed holograms is determined in this temperature range. From these measurements, we extrapolate a lifetime for the fixed hologram refractive index change of 3.7 years at room temperature. (C) 1997 American Institute of Physics.