Fused Quartz and Fused Silica wafers have an exceptionally good transmittance in the 170 to 2500nm range. Fused Silica in general exhibits the best transmission in the UV range.

Click on the link below to view the table of optical characteristic of a 1.0mm thick polished quartz test wafer as a reference: https://docs.google.com/spreadsheet/ccc?key=0AolHUVO7RVi_dEUzQnp2REJDZnhheGt3SndVZEI4dlE

To view the Refractive Index Table click on this link: https://docs.google.com/spreadsheet/ccc?key=0AolHUVO7RVi_dDl6THQzZ0s2clk5V29rOXYyODhZRUE