Schott LaK 31, 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	1.41824715E+00;
B2	4.09404103E-01;
B3	1.15432487E+00;
C1	6.79114675E-03;
C2	2.19284910E-02;
C3	8.03980528E+01;