Broadband Quasi-phase-matching Second-harmonic Generation in 0.5 mol% MgO-doped Periodically Poled Stoichiometric LiTaO₃

Broadband type 0 (ee-e) and type I (oo-e) quasi-phase-matching (QPM) second-harmonic generations (SHGs) are investigated in 0.5 mol% MgO-doped periodically poled stoichiometric LiTaO3 (0.5 mol% MgO:PPSLT). The group-velocity matching (GVM) fundamental wavelength and corresponding QPM crystal grating period are calculated for temperatures from 20 to 200 ◦C. The SHG bandwidths are obtained at different temperatures. The tuning ranges of GVM fundamental wavelength for type 0 and I QPM are 2.575 − 2.590 μm and 2.497 − 2.712 μm for temperature from 20 to 200 ◦C, respectively. The SHG bandwidths are all around 90 nm at 25 (room temperature), 100 and 200 ◦C at a crystal length of 10 mm for type 0 and I QPM. The influence of temperature on the GVM fundamental wavelength and the SHG bandwidth is larger for type I QPM than that for type 0 QPM.