Research on the Response Characteristics of Vanadium Pentoxide Film to the Irradiation of Ultrafast Pulsed Laser

Vanadium pentoxide (V(2)O(5)) is the most stable phase among many transition metal vanadium oxides, and has already been widely used in many fields. In this study, the morphological, structural, and optical responses of V(2)O(5) film to ultrafast laser irradiation was investigated. The third-order nonlinear optical properties of V(2)O(5) film were measured by common Z-scan technique, and the results showed that V(2)O(5) film has self-defocusing and saturable absorption characteristics. The third-order nonlinear absorption coefficient and nonlinear refractive index were calculated to be −338 cm/GW and −3.62 × 10(−12) cm(2)/W, respectively. The tunable saturated absorption with modulation depth ranging from 13.8% to 29.3% was realized through controlling the thickness of vanadium pentoxide film. V(2)O(5) film was irradiated by ultrafast laser with variable pulse energy, and the morphological and structural responses of the V(2)O(5) to the laser with different energy densities were investigated. The irreversible morphological and structural responses of V(2)O(5) films to ultrafast laser irradiation was analyzed using the phase-contrast microscope and Raman spectrum. The chemical structure change from V(2)O(5) to V(6)O(13) was considered the main reason for refractive index modification.