Suppression of quadratic cascading in four-photon interactions using periodically poled media

We demonstrate theoretically that periodically poled materials with a suitable poling period can strongly reduce all χ⁽²⁾:χ⁽²⁾ cascading during χ⁽³⁾ third-harmonic generation and optical parametric amplification in noncentrosymmetric crystals: the calculated reduction is, respectively, 3 and 6 orders of magnitude along the X axis of KTiOPO₄. This is then an original and promising way to achieve efficient pure cubic optical frequency conversion, for the study of three-photon quantum properties.