Plane Windows
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Plane windows are used as substrates for a variety of applications, such as laser windows, output couplers, beamsplitters, beam combiners, mirrors, dichroic filters and plate polarizers. Considerations in selecting window substrates include transmission range, absorption coefficient, incident laser power density and environmental factors such as pressure, temperature, moisture, abrasion and corrosion.
Plane Windows listed under UV / VIS / NIR substrates are specified for applications involving coating wavelengths 193 nm ≤ λ ≤ 2.0 µm. Units for these substrates are given in mm.
Plane Windows listed under IR substrates are specified for applications involving coating wavelengths λ ≤ 2.0 µm. Units for these substrates are given in inches.
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RMI Standard Specifications
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| Materials: |
BK7, UVFS, FS, CaF2, IR grade CaF2, MgF2, BaF2, ZnSe, ZnS, Ge, Si, Sapphire, Cleartran, Infrasil, Suprasil
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Surface Figure:
BK7, UVFS, FS:
CaF2, MgF2, BaF2:
ZnSe, ZnS, Ge, Si, Cleartran:
Sapphire (2 grades):
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Both Surfaces
λ/20 at 633 nm
λ/4 at 633 nm
λ/40 at 10.6 µm
λ/10, or λ/4 at 633 nm
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Surface Quality:
BK7, UVFS, FS:
CaF2, MgF2, BaF2:
ZnSe, ZnS, Ge, Si, Cleartran:
Sapphire (2 grades):
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Both Surfaces
10-5
20-10
40-20
20-10 or 60-40 |
| Diameter Tolerance: |
+ 0.000", – 0.010" |
| Thickness Tolerance: |
± 0.010" |
Wedge:
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≤ 3 arc minutes |
| Bevels: |
0.02"at 45º typical
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| Clear Aperture: |
Exceeds central 85% of diameter |
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