H-ZLAF90A by CDGM

$$n(\lambda) = \sqrt{1 + \frac{2.34543\,\lambda^2}{\lambda^2 - 0.0141722} + \frac{0.462434\,\lambda^2}{\lambda^2 - 0.0612622} + \frac{1.97877\,\lambda^2}{\lambda^2 - 129.818}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-2.44 \times 10^{-6} + 2(1.48 \times 10^{-8})\,\Delta T + 3(-3.78 \times 10^{-11})\,\Delta T^2 + \frac{1.14 \times 10^{-6} + 2(1.44 \times 10^{-9})\,\Delta T}{\lambda - 0.278}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$