Specification	WG50530	WG51050
Thickness	3 mm	5 mm
Thickness Tolerance	±0.3 mm
Diameter Tolerance	+0.0 / -0.2 mm
Surface Quality	20-10 Scratch-Dig
Parallelism	≤10 arcsec
Surface Flatness (@633 nm)	λ/8 over Clear Aperture
Clear Aperture	>90% Diameter
Uncoated Transmission (Raw Data)

Precision Window Selection Guide
Substrate Material	Wavelength Range
Magnesium Flouride (MgF2)	120 nm - 6 μm
Sapphire	150 nm - 5 μm
Calcium Fluoride (CaF2)	180 nm - 8 μm
UV Fused Silica	185 nm - 2.1 μm
Barium Flouride (BaF2)	200 nm - 11 μm
N-BK7	350 nm - 2.0 μm
Silicon (Si)	1.2 - 8 μm
Zinc Selenide (ZnSe)	600 nm - 16 µm
Germanium (Ge)	2 - 16 μm

Features

• Ø1/2" and Ø1" Versions Available
• CaF₂ Substrate
• Wavelength Range: 180 nm - 8 μm

These Calcium Fluoride (CaF₂) High Precision Windows, which are available in Ø1/2" and Ø1" sizes, offer high transmission from the vacuum ultraviolet (180 nm) to the infrared (8 μm). Given its low absorption coefficient and high damage threshold, the calcium fluoride crystal is a popular choice for use with excimer lasers. CaF₂ windows are also commonly used in cryogenically cooled thermal imaging systems.

CaF₂ has many desirable physical and chemical properties. With an Abbe Number of 95, calcium fluoride offers low dispersion. It also has excellent water, chemical, and heat resistance. In dry environments, CaF₂ can be used up to 1000 ^oC, but in the presence of moisture, degradation will occur for temperatures exceeding 600 ^oC. This crystal is also inert to organic chemicals and many acids.

Thorlabs offers High Precision Windows fabricated from various substrate materials for use in a large variety of laser and industrial applications. We also offer laser windows, which have wavelength-specific AR coatings centered around commonly used laser wavelengths, and Brewster windows, which are known to eliminate p-polarization reflectance.