Formation of nonlinear optical Na₂TeW₂O₉ crystals and laser irradiation in tungsten–tellurite glasses

The crystallization behavior of 25Na2O–50WO3–25TeO2 glass was examined to develop transparent glass-ceramics containing nonlinear optical Na2TeW2O9 crystals. It was clarified from XRD analysis and Raman scattering spectra that a metastable crystalline phase is formed initially and the stable crystalline phase of Na2TeW2O9 is created through the transformation of the metastable phase. Laser irradiations (continuous wave Yb:YVO4 fiber laser, wavelength of 1080 nm) with the condition of the laser power of P = 0.55 W and scanning speed of S = 2.3 μm/s created the patterning of homogeneous crystals lines. The crystalline phase in the laser irradiated part was proposed to be the metastable crystalline phase from micro-Raman scattering spectra.