H-ZLAF89L by CDGM

$$n(\lambda) = \sqrt{1 + \frac{2.3325\,\lambda^2}{\lambda^2 - 0.0127519} + \frac{0.338027\,\lambda^2}{\lambda^2 - 0.0535632} + \frac{1.63569\,\lambda^2}{\lambda^2 - 114.949}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-5.79 \times 10^{-7} + 2(1.36 \times 10^{-8})\,\Delta T + 3(-1.97 \times 10^{-11})\,\Delta T^2 + \frac{9.06 \times 10^{-7} + 2(8.65 \times 10^{-10})\,\Delta T}{\lambda - 0.261}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$