S-LAL19 by Ohara

$$n(\lambda) = \sqrt{1 + \frac{0.973998\,\lambda^2}{\lambda^2 - 0.00379333} + \frac{0.958186\,\lambda^2}{\lambda^2 - 0.0177575} + \frac{1.20163\,\lambda^2}{\lambda^2 - 83.799}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[4.19 \times 10^{-6} + 2(1.04 \times 10^{-8})\,\Delta T + 3(7.25 \times 10^{-13})\,\Delta T^2 + \frac{4.73 \times 10^{-7} + 2(4.97 \times 10^{-10})\,\Delta T}{\lambda - 0.202}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$