55% conversion efficiency to green in bulk quasi-phase-matching lithium niobate

High voltage and liquid electrodes were used for periodic poling of lithium niobate. A sample with a period of 6.80 µm was used for first-order frequency doubling of 1064 nm Q-switched Nd:YAG light with an average power conversion of 55%, implying greater than 90% power conversion at the peak of the pulse. The effective nonlinear coefficient for both Q-switched and continuous-wave measurements was ~15 pm/V

532nm pumped optical parametric oscillator in bulk periodically poled lithium niobate

We report a quasi-phase-matched optical parametric oscillator pumped by the second harmonic of a single frequency Q-switched Nd:YAG laser. Both the frequency doubling to 532 nm and the parametric oscillation are performed in periodically poled lithium niobate crystals with a nonlinearity of ~15 pm/V. The OPO has been operated in 'singly resonant' and 'doubly resonant' configurations. The threshold in the singly resonant case was ~0.14 J/cm2, more than one order of magnitude below the damage limit. OPO tuning from 945 nm to 1225 nm was achieved by changing both the period of domain reversal (from 6.8 to 6.85µm) and the temperature of the crystal

Multiple-crystal X-ray topographic characterization of periodically domain-inverted KTiOPO4 crystal

A periodically domain-inverted KTiOPO4 crystal has been characterized for the first time by multiple-crystal multiple-reflection x-ray topography. The striation contrast within the domain- inverted regions has been revealed in high strain-sensitivity reflection topographs. The origin of formation of the striation contrast and the mechanism of domain inversion in KTiOPO4 are discussed in terms of the structural characteristics of KTiOPO4