--- /dev/null
+Schott BK6, 313nm - 2325nm\r
+USER\r
+2 1\r
+SQRT(1+B1*wvl^2/(wvl^2-C1)+B2*wvl^2/(wvl^2-C2)+B3*wvl^2/(wvl^2-C3))\r
+0\r
+B1 1.002819e+000\r
+C1 5.747159e-003\r
+B2 3.095685e-001\r
+C2 1.920457e-002\r
+B3 1.018406e+000\r
+C3 1.087608e+002\r