H-LAK5A by CDGM

$$n(\lambda) = \sqrt{1 + \frac{1.54437\,\lambda^2}{\lambda^2 - 0.00815901} + \frac{1.00067\,\lambda^2}{\lambda^2 - 88.9111} + \frac{0.219124\,\lambda^2}{\lambda^2 - 0.0267011}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-4.1 \times 10^{-6} + 2(1.07 \times 10^{-8})\,\Delta T + 3(-1.69 \times 10^{-11})\,\Delta T^2 + \frac{5.87 \times 10^{-7} + 2(1.27 \times 10^{-9})\,\Delta T}{\lambda - 0.095}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$