The optical properties of fluorozirconate glasses are determined. The composition of glass selected for investigation is 58ZrF4, 36BaF2, 6LaF2, 10AlF3, 10NaF. The light transmittance of the glass falls in the range from 0.23 to 7.5 ?m. The mean dispersion of the examined glass is the same that of water, 0.0065, and the Abbe number is 77. A very important advantage of fluorozirconate glass is the fact that it satisfies the condition of adjusted interferometry when water is the immersion medium.
"Low-dispersion fluorozirconate glass with spectral dispersion of refractive index similar to that of water," Optical Engineering 36(6), (1 June 1997). https://doi.org/10.1117/1.601186