S-LAL54 by Ohara

$$n(\lambda) = \sqrt{1 + \frac{1.4191\,\lambda^2}{\lambda^2 - 0.00726647} + \frac{0.258417\,\lambda^2}{\lambda^2 - 0.0263842} + \frac{1.07386\,\lambda^2}{\lambda^2 - 102.555}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.76 \times 10^{-6} + 2(1.3 \times 10^{-8})\,\Delta T + 3(-3.27 \times 10^{-11})\,\Delta T^2 + \frac{3.37 \times 10^{-7} + 2(4.72 \times 10^{-10})\,\Delta T}{\lambda - 0.262}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$