MEASUREMENT OF REFRACTIVE-INDEXES AND THERMAL REFRACTIVE-INDEX COEFFICIENTS OF THE TI-MG-LINBO3 CRYSTAL

The principal refractive indices and thermal refractive index coefficients for the LiNbO3 crystal dope with 5 mol. % Mg and 0.2 mol. % Ti have been measured by the minimum deviation method at the wavelengths 539.8, 632.8, 1079.5, and 1341.4 nm in the temperature range 15-150-degrees-C. The constants of Sellmeier's equation are given in this temperature range. On the basis of the measured results, the thermal refractive index coefficients at these wavelengths have also been obtained. The obtained results were used in the calculation of the type I critical phase-matching angles for 1064- and 1079.5-nm second-harmonic generation (SHG) at room temperature and of the noncritical phase-matching temperature for the 1079.5-nm SHG for the Ti:Mg:LiNbO3 crystal. The calculated and experimental results are in excellent agreement.