H-ZLAF71AGT by CDGM

$$n(\lambda) = \sqrt{1 + \frac{1.54173\,\lambda^2}{\lambda^2 - 131.964} + \frac{2.0347\,\lambda^2}{\lambda^2 - 0.0125481} + \frac{0.264812\,\lambda^2}{\lambda^2 - 0.0559795}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.11 \times 10^{-6} + 2(1.41 \times 10^{-8})\,\Delta T + 3(-2.89 \times 10^{-11})\,\Delta T^2 + \frac{8.98 \times 10^{-7} + 2(1.1 \times 10^{-9})\,\Delta T}{\lambda - 0.259}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$