Studied on Characteristics of Mg (4.5 Mol%)-Doped LiNbO3 Crystal Using Li Vapor Transport Equilibration

It is studied that influence of Li vapor transport equilibration (VTE) on surface refractive index of congruent Mg (4.5 mol%):LiNbO3crystal at wavelength of 1536 nm. The results show the ordinary index nodecreases when t < 40 h, then recoveries slightly and tends to a constant when t >100 h. The extraordinary index nehas the VTE effects as similar as no, but the alteration amplitude is smaller than no. The secondary ion mass spectrometry) study shows that the VTE induces Mg diffusion within the crystal in an inhomogeneous Mg depth profile, depending on the VTE duration. The neutron activation analysis shows that the VTE hardly induces Mg evaporation away from the crystal. First, the Mg ions of crystal internal diffused to the surface in the early stage of VTE, and then they diffused slowly back into the bulk of the crystal toward equilibrium when Li concentration tends to equilibrium.