Manifestation of second-order nonlinear optical effects in KTP and RTP nanocrystallites incorporated into polymer matrices

Strong second-order optical effects in KTiOPO4 (KTP) nanocrystallites incorporated into polymethylmethacrylate (PMMA) matrices have been found. The maximally achieved value of the effective second-order susceptibility was equal to about 2.2 pm/V at laser wavelength 1320 nm and at liquid helium temperature (LHeT). It corresponds to concentration of the nanocrystallites of about 5.6% in weighting units. Incorporation of Rb ions and finally conversion to RbTiOPO4 (RTP) nanocrystallites substantially reduces the effect. A similar decrease is observed when the PMMA matrix is replaced by polyvinylcarbazole (PVK) matrix.