Efficient cubic third harmonic generation in KTiOPO/sub 4/

Summary form only given. The experiments on quantum optical correlations partly depend on efficient optical frequency conversion: in the case of quadratic interactions, a second-harmonic generation efficiency of few percents is required to observe the correlations. Such conversion efficiencies are very difficult to reach for cubic processes because the associated /spl chi//sup (3)/ coefficients are weak. Consequently, the specific quantum optical effects linked to cubic parametric processes have never been studied. In the present work, we report the first experiments of efficient third harmonic generation (THG) phase-matched in KTiOPO/sub 4/ (KTP).