Schott Sk12, 334nm - 2325nm
USER
2 1
SQRT(1+B1*wvl^2/(wvl^2-C1)+B2*wvl^2/(wvl^2-C2)+B3*wvl^2/(wvl^2-C3))
0
B1	1.16982669E+00;
B2	2.97450370E-01;
B3	9.65847815E-01;
C1	6.52887127E-03;
C2	2.14033820E-02;
C3	1.05089898E+02;