H-ZLAF50D by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.497441\,\lambda^2}{\lambda^2 - 0.0285447} + \frac{1.6778\,\lambda^2}{\lambda^2 - 0.00788379} + \frac{1.32327\,\lambda^2}{\lambda^2 - 94.0514}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.43 \times 10^{-6} + 2(1.84 \times 10^{-8})\,\Delta T + 3(1.12 \times 10^{-10})\,\Delta T^2 + \frac{9.58 \times 10^{-7} + 2(3.67 \times 10^{-9})\,\Delta T}{\lambda - 0.085}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$