Effect of WO3 in the third-order optical nonlinearities of tungsten lead pyrophosphate glasses

Abstract

The binary glassy system Pb2P2O7-WO3 demonstrates promising photonics applications owing to its high polarizability and chemical stability. The domain of glass's chemical state and linear and nonlinear optical properties have been investigated using X-ray photoelectron spectroscopy (XPS), UV–visible spectroscopy, and the Z-scan technique, respectively. The optical absorption spectra revealed that the absorption edge was redshifted with increased WO3 content, suggesting a decrease in bandgap energy. Nonlinear refractive index increased with the WO3 content from an average value of 0.70 x 10−19 m2 W−1 to 0.98 x 10−19 m2 W−1. Such an increase is due to the rise of non-bridging oxygens and the polarizability of W6+ and W5+ species. XPS studies found that a high concentration of WO3 leads to the transformation of the oxidation state of W6+ and W5+ related to the presence of oxygen vacancies. Therefore, our high nonlinear refractive index and polarizability results indicate that the glass system studied here is a potential candidate for photonic devices.