Influence of dopants on the optical damage and absorption edge in doped LiNbO3 crystals

The optical damage resistance ability of the co-doped M:Fe:LiNbO3 crystals with 0.03 wt% Fe2O3 and various concentration of M (M = Mn, Mg, or Zn,) were measured experimentally. The shift of the fundamental absorption edge as well as the absorption coefficient was obtained in order to investigate their defect structures. A method of confirming the polarization ability dimension of doped ions is brought forward. The indirect transition properties of the fundamental absorption edge below 3.8 eV were investigated experimentally. Possible models to explain the experiments results are discussed.