H-QK30GTI by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.447701\,\lambda^2}{\lambda^2 - 0.014476} + \frac{0.725301\,\lambda^2}{\lambda^2 - 0.00347765} + \frac{0.92451\,\lambda^2}{\lambda^2 - 101.678}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.13 \times 10^{-5} + 2(1.92 \times 10^{-8})\,\Delta T + 3(-2.23 \times 10^{-11})\,\Delta T^2 + \frac{3.36 \times 10^{-7} + 2(1.05 \times 10^{-10})\,\Delta T}{\lambda - 0.2}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$