In this study, stacked films of barium oxide (BaO) comprising platinum nanosheets in its structure are designed as electro-optical filters applicable in terahertz technology. The layers were fabricated by the thermal evaporation technique. It was shown that insertion of 50 nm and 100 nm thick Pt nanosheets between stacked layers of BaO improves the crystallinity of the layers by reducing the strains and defect concentrations. In addition, the light absorption and optical conduction is enhanced by more than 300%, 900% and 100 % in the ultraviolet (3.5-4.10 eV), visible (1.80-3.10 eV) and infrared (1.10-1.75 eV) ranges of light, respectively. The insertion of Pt nanosheets led to an increase in the dielectric constant (ε_r) values by over 104%. Specifically, ε_r values were initially 1.2–1.5, 1.6–1.8, and 1.8–2.0 in the ultraviolet, visible, and infrared light ranges, respectively. Upon incorporating Pt nanosheets with a thickness of 200 nm, these ε_r values increased to 1.4–1.7 in the ultraviolet, 1.8–3.6 in the visible, and 3.7–3.9 in the infrared ranges. Significant increase in the terahertz cutoff frequency from ~2.5 THz to ~15.35 THz was achieved in the infrared range of light. Moreover, the optical conductivity parameters which were obtained with the help of Drude-Lorentz electro-optical analysis showed remarkable enhancement in the free carrier concentration and in the drift mobility of the BaO optical filters from 5×〖10〗^18 cm-3 and 0.47 cm2/Vs to 7×〖10〗^18 cm-3 and 2.03 cm2/Vs to 9×〖10〗^18 cm-3 and 2.03 cm2/Vs upon insertion of Pt nanosheets of thicknesses of 100 nm and 200 nm, respectively. Furthermore, the temperature dependent electrical conductivity measurements has shown that Pt nanosheets increased the electrical conductivity of BaO by eight orders of magnitude. The features of BaO stacked layers comprising Pt nanosheets are promising for terahertz technology applications as waveguides and wideband optical filters.