A partly periodically poled KTiOPO<sub>4</sub> (KTP) crystal has been designed to integrate quasi-phase-matched second-harmonic generation (QPM SHG) with sum-frequency generation in one crystal for generating a third-harmonic beam. The highest conversion efficiencies of 45% and 3% have been achieved in our experiments for QPM SHG and third-harmonic generation, respectively, by use of picosecond laser pulses at 1.327 µm . We have also discovered that periodically poled KTP has slightly different indices (<i>n</i><sub>z</sub>) from bulk KTP.
© 2001 Optical Society of America
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4360) Nonlinear optics : Nonlinear optics, devices
(190.4400) Nonlinear optics : Nonlinear optics, materials
(230.0230) Optical devices : Optical devices
Xiaodong Mu and Yujie J. Ding, "Efficient third-harmonic generation in partly periodically poled KTiOPO4 crystal," Opt. Lett. 26, 623-625 (2001)