Doubling the frequency of depleted fundamental waves in periodically poled KTiOPO4

Frequency doubling of a diode-pumped Nd:YAG laser in 1 and 2 cm long periodically poled KTiOPO4 wafers has been investigated. Up to 60% doubling efficiency has been achieved. The good agreement obtained between measured results and those calculated by numerical integration of the coupled wave equations demonstrate that the efficiency is limited by the basic process of backconversion and dephasing rather than by thermal effects.