Ferroelectric AgNa(NO2)2 crystals as novel highly efficient nonlinear optical material: Phase matched second harmonic generation driven by a spontaneous and electric field induced polarizations

Paper reports the second harmonic generation(SHG) in ferroelectric AgNa ( NO 2 ) 2 crystals being driven by the spontaneous and electric field induced polarizations. Obtained results are interpreted within the phenomenological theory which considers the free energy describing the interaction between the spontaneous or electric field induced polarizations and spatially inhomogeneous electric polarizations resulted from propagating optical waves. Relatively high magnitudes of the effective second order nonlinear optical (NLO) susceptibilities in these crystals are combined with several phase matching geometries which allows to consider them as high-performance materials for potential NLO applications, such as parametric generation and amplification, frequency doubling, or other applications that require high-efficient frequency conversion. In addition, an anomalously large response of NLO susceptibilities with respect to an applied electric field has been found in the vicinity of the Curie point. This may also have a number of applications, especially in those devices where an efficient tunable control of SHG intensity is demanded

Spontaneous and electric field induced quadratic optical nonlinearity in ferroelectric crystals AgNa(NO2)2

We demonstrate the second harmonic generation (SHG) in ferroelectric AgNa(NO2)2 crystals resulting from the spontaneous and electric field induced polarizations. Relatively high effective nonlinear optic (NLO) susceptibility is combined in this crystals with the existing several phase matching geometries of NLO interaction. Anomalously large response of SHG with respect to an applied electric field has been found in the vicinity of the paraelectric-to-ferroelectric phase transition. The behavior of NLO properties in the ferroelectric phase and especially in the region of the Curie point is discussed within the phenomenological theory