H-ZLAF50E by CDGM

$$n(\lambda) = \sqrt{1 + \frac{1.22239\,\lambda^2}{\lambda^2 - 0.00445444} + \frac{0.95286\,\lambda^2}{\lambda^2 - 0.0229974} + \frac{1.37994\,\lambda^2}{\lambda^2 - 99.1991}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.15 \times 10^{-6} + 2(1.32 \times 10^{-8})\,\Delta T + 3(-1.72 \times 10^{-11})\,\Delta T^2 + \frac{6.09 \times 10^{-7} + 2(4.6 \times 10^{-10})\,\Delta T}{\lambda - 0.211}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$