χ⁽²⁾ Grating in Ru Derivative Chromophores Incorporated within the PMMA Polymer Matrices

We have found that Ru derivative chromophores incorporated into the PMMA polymer matrices might be considered as promising materials for optical poling. The maximally achieved effective second-order optical susceptibility for the wavelength 1.89 μm is about 1.94 pm/V. The investigated composites possess metastable trapping levels originating both from the d states of Ru and due to effective charge transfer due to the presence of π-conjugated states. Because of incorporation of the chromophore into polymer matrices, we have revealed that the maximal susceptibility is observed at 5−6% of the chromophore in weighting units. The further increase of the second-order susceptibility is limited by the appearance of chromophore agglomerates substantially restraining second-order susceptibilities. The investigated composites possess long-lived χ (2) grating, which decreases less than 76% after 600 min of laser treatment. The electrostatic field causes additional reanimation of the second harmonic generation during the decay regime. The electron microscopy pictures clearly confirm appearance of the χ (2) grating.