Full Spectrum Fused Silica: JGS3 (China), equivalent to Suprasil 300 (Heraeus). JGS3 combines excellent physical properties with outstanding optical characteristics in the deep UV and the IR wavelength range. It is the preferred material for transmission optics; it is usually used in IR applications and also in those requiring very wide wavelength range from DUV to MIR. However the most common Fused Silica for infrared use is quite a bit more expensive than Silicon and slightly less expensive than Calcium Fluoride or ZnS Multi-spectral grade. Also a commercial quality of IR quartz often contains many small bubbles and should only be used for non-imaging applications.