An optical prism is a block of optical material cut into a geometrical shape designed to modify the incident light beam by altering its direction, rotational angle, or diffraction. In optical systems, prisms are utilized to redirect or separate the light signal based on its wavelengths.
Various optical materials can be employed to manufacture prisms, depending on the type of prism and the wavelength range it will be used in. These materials include optical glass such as B270, H-K9L/NBK7, F2, N-SF11, fused silica, IR materials like CaF2, BaF2, MgF2, silicon, and germanium, as well as sapphire, among others.
The manufacturing of optical prisms adheres to specific dimensional tolerances and specifications, as outlined in the table below:
- Dimensional Range: From 0.3mm to 300mm
- Dimensional Tolerances: Typically +/- 0.1mm (normal) or +/- 0.05mm
- Surface Flatness: Up to Lambda/10
- Surface Quality: S&D 40/20
- Angle Tolerance: Up to +/- 1 arcmin
Prisms can also be coated with anti-reflective (AR) coatings to reduce signal reflection on the surface or with reflective coatings to enhance signal reflection at specific wavelengths.