--- /dev/null
+Schott BK3, 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 1.005827e+000\r
+C1 6.174161e-003\r
+B2 2.120964e-001\r
+C2 1.877926e-002\r
+B3 8.982909e-001\r
+C3 8.887350e+001\r