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Angular Quasi-Phase-Matching in Periodically Poled Uniaxial and Biaxial Crystals

This article deals with a general description of Angular Quasi-Phase-Matching (AQPM) in uniaxial and biaxial crystals for second-order nonlinear optical interactions. Such an exhaustive and generalized angular-dependent approach of AQPM reveals new directions of propagation with efficient parametric frequency conversion. These AQPM solutions are studied by depicting the corresponding topologies and associated symmetries. The theoretical overview is fully validated and illustrated by measurements. We clearly demonstrate the benefits of such a generalized approach, both in the case of two emblematic periodically poled (PP) crystals: 5%MgO-doped PPLiNbO3 (5%MgO:PPLN) and Rb-doped PPKTiOPO4 (PPRKTP). These developments should stimulate new potential applications in nonlinear frequency conversion.