Nonvolatile two-step, two-color holography with continuous-wave lights for both congruent and near-stoichiometric LiNbO_(3):Fe

摘要

We have studied theoretically the steady-state nonvolatile two-step, two-color holographic recording performance for both the congruent and the near-stoichiometric LiNbO_(3):Fe based on the two-center model (the deep-trap and the shallow-trap centers are Fe~(2+)/Fe~(3+) and (Nb_(Li))~(4+)/(Nb_(Li))~(5+), respectively). The results show that the direct electron exchange between the Fe~(2+)/Fe~(3+) centers and the (Nb_(Li))~(4+)/(Nb_(Li))~(5+) centers due to the tunneling effect dominates the charge-transfer process during the nonvolatile two-step, two-color holography and determines the two-step, two-color holography performance in LiNbO_(3):Fe. We have further studied the effects of the crystal stoichiometry on the performance of the two-step, two-color holography. It is shown that, as far as the total space-charge field is considered, the nonvolatile two-step, two-color holography performance in the near-stoichiometric LiNbO_(3):Fe is much better than that in the congruent LiNbO_(3):Fe within the intensity range reachable by the continuous-wave lights.