S-LAL58 by Ohara

$$n(\lambda) = \sqrt{1 + \frac{1.06369\,\lambda^2}{\lambda^2 - 0.01852} + \frac{0.744939\,\lambda^2}{\lambda^2 - 0.00116296} + \frac{1.59179\,\lambda^2}{\lambda^2 - 156.636}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-6.04 \times 10^{-7} + 2(8.69 \times 10^{-9})\,\Delta T + 3(-3.71 \times 10^{-11})\,\Delta T^2 + \frac{6.22 \times 10^{-7} + 2(5.61 \times 10^{-10})\,\Delta T}{\lambda - 0.185}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$