Stability of fixed holograms in LiNbO3

Abstract

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 °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.

Holographic scattering as a technique to determine the activation energy for thermal fixing in photorefractive materials

“…Much research work has been done to identify the mobile ions and to elucidate the mechanism of thermal fixing in order to control the fixing and development processes. [4][5][6][7][8][9] In most cases protons are identified as the only mobile ion below 180°C. 4,5 The individual processes of ion migration follow an Arrhenius law and are characterized by a particular thermal activation energy and a preexponential factor.…”