<title>Refractive index dispersion measurements of congruent and stoichiometric LiTaO<formula><inf><roman>3</roman></inf></formula></title>

We present a temperature-dependent Sellmeier equation for congruent and stoichiometric LiTaO₃. The refractive indices in the range of 0.39-4.1 micrometers were determined by scanning the pump lasers wavelength and finding the QPM second harmonic wavelength for a series of period- temperature pairs, and from QPM OPO measurements. The obtained new Sellmeier coefficients were used to calculate the QPM wavelengths of the idler and signal for a PPSLT OPO pumped at 1064 nm. An OPO based on PPSLT was demonstrated. The idler-tuning range was 4.1828-3.9898 micrometers for temperatures of 40-200 degree(s)C. The obtained wavelengths were in good agreement with our predictions.