H-ZLAF4LB by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.303788\,\lambda^2}{\lambda^2 - 0.0500877} + \frac{2.22146\,\lambda^2}{\lambda^2 - 0.0118758} + \frac{1.54969\,\lambda^2}{\lambda^2 - 113.958}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[2.77 \times 10^{-7} + 2(1.42 \times 10^{-8})\,\Delta T + 3(-4.04 \times 10^{-11})\,\Delta T^2 + \frac{8.52 \times 10^{-7} + 2(9.84 \times 10^{-10})\,\Delta T}{\lambda - 0.245}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$