Z-scan measurements and optical limiting response of V₂O₅:MoO₃ thin films

The objective of this study is to investigate the laser-induced third-order optical nonlinearity in vanadium pentoxide (V₂O₅) thin films and doped molybdenum vanadium pentoxide thin films. The work presents the synthesis of V₂O₅ (100 nm) and MoO₃ (8wt. %) doped V₂O₅ thin films using the standard thermal evaporation technique at a glass substrate with a substrate temperature of 250 °C at two different thicknesses of 100 nm and 200 nm. The XRD shows that films exhibit orthorhombic structure with strong orientation (200) and also with doping, there is variations in lattice parameters as well as with thickness and UV–visible spectra showing the two-photon absorption. A pulsed Nd-YAG laser (532 nm) is used as a source of light to estimate the nonlinear index of refraction (n₂), intensity-dependent absorption coefficient (β), and nonlinear susceptibility (χ3) by using the z-scan methodology. Optical limiting behavior with a limiting threshold is also reported. The presence of significant third order optical nonlinear susceptibility (χ³) and a comparatively small limiting threshold (TL) for visible laser beam suggests that MoO₃: V2O₅ thin films have a lot of potential for photonic applications. (author)