Effect of nitrogen addition on optical properties of fluorozirconate glasses

The linear and non-linear optical properties of fluorozirconate glasses with and without nitrogen, namely ZrF₄? BaF₂? LaF₃? AIF₃ and ZrF₄? BaF₂? LaF₃? AIF₃? AIN, have been studied. The glass containing nitrogen exhibits a 5 nm shift of the transmittance edge in the UV region towards longer wavelength, whereas there is no change in the IR transmittance. Measurements show a small increase in the linear index of refraction in the visible region and a small decrease in the non-linear (intensity-dependent) refractive index coefficient n₂. Longitudinal and transverse sound velocities estimated from Brillouin-scattering experiments for both glasses amount to 6311 and 4514 ms^?1, respectively.