Phase Retarding Mirrors
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Phase Retarding Mirrors are designed to produce a specific phase shift between the S and P polarization components of an incident CO2 laser beam. Mirrors designed for zero phase shift maintain the incident polarization state in the reflected beam. Mirrors designed for λ/4 (90º) phase shift convert a linearly polarized beam into a circularly polarized beam. Mirrors designed for λ/8 (45º) phase shift convert a linearly polarized beam into an elliptically polarized beam.
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RMI Standard Specifications
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| Design wavelength: |
10.6 µm |
Angle incidence:
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45º |
| Materials: |
Si, Cu |
Surface Figure:
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λ/40 [λ/20] at 10.6 µm, S1
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Surface Quality:
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40-20, S1 Fine grind, S2
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| Diameter Tolerance: |
+ 0.000", – 0.010" |
| Thickness Tolerance: |
± 0.010" |
| Wedge: |
< 3 arc minutes |
| Bevels: |
0.010" – 0.030" at 45º |
| Clear Aperture: |
Central 85% of diameter |
| Reflectance: |
R ≥ 98.5% |
| Retardation: |
0: 0º ± 6º λ/8: 45º ± 3º λ/4: 90º ± 6º |
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