S-LAM58 by Ohara

$$n(\lambda) = \sqrt{1 + \frac{1.70985\,\lambda^2}{\lambda^2 - 0.0100852} + \frac{0.173343\,\lambda^2}{\lambda^2 - 0.0470891} + \frac{1.64834\,\lambda^2}{\lambda^2 - 157.469}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[2.9 \times 10^{-6} + 2(1.29 \times 10^{-8})\,\Delta T + 3(-3.62 \times 10^{-11})\,\Delta T^2 + \frac{6.72 \times 10^{-7} + 2(7.76 \times 10^{-10})\,\Delta T}{\lambda - 0.243}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$