Determination of type I phase matching angles and conversion efficiency in KTP.

Measurements of the conversion efficiency of second-harmonic generation in KTP (KTiOPO(4)) by the use of type I phase matching for different fundamental wavelengths of a mode-locked picosecond Ti:sapphire laser are presented. The observed phase matching angles are in agreement with the calculated phase matching curves. At a fundamental wavelength of 834 nm and an intensity of 100 MW/cm(2) the conversion efficiency is 4% at maximum, and the corresponding effective nonlinear coefficient d(eff) is equal to 0.32 pm/V. The experimental values of d(eff) are related to d(11) (= 0.46 pm/V) of quartz and are in line with the predictions.