Third-order nonlinearity and functional data analysis of ADP-doped PVA/PVP polymer composites

Abstract

The structural dependence of nonlinear optical properties associated with ADP-doped PVA/PVP polymer composites is discussed in this work. Polymer composites are fabricated using the solution casting method. X-ray diffraction (XRD) was used to perform structural analysis on these samples whose average crystallite size increases with an increase in dopant concentration. Results from UV–Vis–NIR spectra show that the samples are transparent in the IR region. The Z-scan technique was established by following the method described by Sheik-Bahae et al. The shape of the open aperture plot suggests that the samples exhibit two-photon absorption. The NLO properties such as nonlinear absorption coefficient ([Formula: see text], two-photon absorption cross-section ([Formula: see text] and the imaginary part of third-order nonlinear susceptibility [Formula: see text] were investigated at 1064 nm and these values were found to be in the order of [Formula: see text][Formula: see text]W/cm, [Formula: see text][Formula: see text]cm4/GW and [Formula: see text][Formula: see text]esu, respectively. The open aperture Z-scan method yielded optical limiting data, from which the optical limiting threshold was calculated to be in the order of [Formula: see text][Formula: see text]W/m2. Functional data analysis uses a suitable basis representation to assess the functional correlation between global and local variables.