Schott SF 56A, 405nm - 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	1.70579259E+00;
B2	3.44223052E-01;
B3	1.09601828E+00;
C1	1.33874699E-02;
C2	5.79561608E-02;
C3	1.21616024E+02;