Influence of Mg dopant on the third-order nonlinear optical properties of CdS-PVP nanocomposite films

• Mg dopant dependent third-order nonlinear optical properties of CdS-PVP nanocomposite films are studied for nonlinear optical device fabrication.
• Nonlinear optical parameters of CdS-PVP film are increased with increasing Mg content.
• The maximum third-order nonlinear optical susceptibility (χ3) and figure of merit are found to be about 1.432×10−4 esu and 8.558×10−9 esu m for 7 mol% Mg doped film.
• The estimated χ3 is two to three orders of magnitude larger than that of the CdS film.

Third-order nonlinear optical properties of Mg doped CdS-PVP films have been studied by Z-scan technique with 5 ns pulses, mod-locked Nd-YAG laser with a frequency doubled at 532 nm. The nonlinear refractive indices and nonlinear absorption coefficients were in the order of 10−10 cm2/W and 10−3 cm/W and they are characterized with self-defocusing and saturable absorption behavior. The maximum third-order nonlinear optical susceptibility (χ3) and figure of merit are found to be about 1.432×10−4 esu and 8.558×10−9 esu m, respectively. The estimated χ3 is two to three orders of magnitude larger than that of the CdS film.