S-LAH60V by Ohara

$$n(\lambda) = \sqrt{1 + \frac{2.05082\,\lambda^2}{\lambda^2 - 0.0116036} + \frac{0.208475\,\lambda^2}{\lambda^2 - 0.0526489} + \frac{1.31486\,\lambda^2}{\lambda^2 - 99.3807}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[8.6 \times 10^{-6} + 2(1.11 \times 10^{-8})\,\Delta T + 3(-1.86 \times 10^{-11})\,\Delta T^2 + \frac{8.29 \times 10^{-7} + 2(9.24 \times 10^{-10})\,\Delta T}{\lambda - 0.257}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$