Optical Components

Z-Cut Cultured Crystal Quartz Windows

BPO supplies optical quality cultured quartz windows and blanks. Z-oriented components are available up to 4.000" in diameter. Very few materials match the useful transmission range and physical properties of optical quality cultured quartz. This material is reproducible, available and affordable.

For over 20 years, BPO specialists have been selecting appropriate quality and cuts of crystal quartz for optical and electronic applications. Critical visual inspection, x-ray diffraction orientation of one or more planes and acid-etch topographical evaluation ensure the most appropriate material to fill your specific needs.

Our windows are chemically polished. The process used to remove the last few microns of material from each surface is basically a mild etch and produces a true single-crystal surface. The polished windows meet or exceed most standard commercial quality requirements. While flatness and parallelism vary with diameter and thickness, wedge is usually less than 0.0005".

For more stringent processing requirements, we can supply inspected, oriented blanks for final finishing at an optical facility of your choice.

A representative inventory of finished windows is maintained. Diameters from 0.500" to 3.000", and thicknesses from 0.020" to 1.000" are available. UV grade windows and blanks are available for more demanding optical and electronic applications. We regularly supply crystal quartz substrates as thin as 0.001", and radiation absorption plates to 2.000" in thickness.

Standard Tolerances

Diameter +/- 0.002"
Thickness +/- 0.002"
Surface Finish

Chemical polish: meets or exceeds 40-20 with respect to processing induced artifacts

Flatness Within 5 waves at 6:1 ratio
Parallelism Within 0.0005"
Orientation +/- 30 minutes
Minimum edge chamfers

Other orientational and dimensional tolerances available

Material Characteristics

Useful transmission range 0.15 to 3.5 microns
Far IR -50 to 200+ microns
Inclusions 3 per cc (greater than 25 microns)
Optical homogeneity 1/10th fringe per inch (UV grade)
Optical activity parallel to Z axis 21° 43'/mm (sodium light)
Index of refraction 1.55 (visible light)
Physical / Electronic Properties
Chemical formula SiO2
Crystal class Trigonal
Density 2.66 x 103 kg/m3 @ 25°C
Melting point 1750°C
Curie point 573°C
Moh's hardness 7
Specific gravity 2.649 @ 20°C
Dielectric constant e11 = 4.58 e33 = 4.70
Molecular weight 60.1
Solubility Non-hydroscopic in most atmospheric liquids
Expansion coefficients At 0°C (10-6): parallel to Z -7.0 perpendicular to Z -12.9