Single Crystal Sapphire Facts

The angular relationship between the inherent optical axis of the crystal and the required part is known as orientation. Zero Degree or C-Axis, C-Plane windows and lenses are most common when crystalline orientation is specified. Each orientation has specific gains in specialized areas of use. When no particular crystal axis is defined, random orientation sapphire usually will suffice and can be more cost effective.

Typical choices for part orientation are:

  • Zero Degree: The direction of view is parallel to the optical axis of the crystal
  • 90 Degree: The direction of view is perpendicular to the optical axis of the crystal
  • C-Axis: In a rod, the direction along its length. In a window, the direction perpendicular to the face
  • M-Plane: The plane containing the optic axis (C) and inclined 30 degrees to the A-axis
  • A-Plane: The plane that is perpendicular to the A-axis, containing the C-axis
  • R-Plane: A plane inclined 57.5667 degrees to the optic axis and in the same zone as the M-plane
  • Random: There is no specified relationship between the part and the crystalline orientation. The part is manufactured without concern about orientation