--- /dev/null
+Schott BK7, 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 1.039612e+000\r
+C1 6.000699e-003\r
+B2 2.317923e-001\r
+C2 2.001791e-002\r
+B3 1.010469e+000\r
+C3 1.035607e+002\r