We report a characterisation of a flux-grown periodically poled KTiOPO4 crystal used for second-harmonic generation in a diode laser source, that operates with fundamental radiation tunable around 1083nm wavelength. The conversion efficiency is measured for the three different grating periods of the crystal, as a function of input wavelength, crystal temperature and fundamental power. The measurements were fitted to the theoretical model of Boyd and Kleinman for frequency conversion of focused Gaussian beams. This enabled us to determine the temperature and wavelength dependence of the difference in refractive index between the interacting waves.
- Non-linear optical coefficient
- Periodically poled crystal
- Second-harmonic generation