Right Angle Prism
Right angle prisms are used as reflectors. They may reflect an input beam at 90° or 180° depending on the configuration or placement. They are preferred over mirrors due to precision and ease of alignment.
Application Notes
- Generally used to achieve a 90% light path band.
- It is usually preferred over an inclined mirror as it is easy to mount and can handle external mechanical stresses.
- Very high transmission can be achieved by using the hypotenuse face in Total Internal Reflection mode and with entrance and exit surface anti reflection coated.
- If the hypotenuse faces may not be kept clean due to environmental conditions it is advisable to aluminize hypotenuse surface.
- It can be used as a path-folding prism in constant deviating mode when the light enters the prism from the hypotenuse, suffers reflections on the perpendicular faces and exits from the hypotenuse face.
Specification
- Material : BK7 or Fused Silica
- Size : From 2 mm to 50 mm
- Dimensional Tolerance : + 0.1 mm
- Surface accuracy : 2?
- Surface quality : 60:40
- Angle Tolerance : +5 arc min
- Bevel : 0.3 mm X 45°
Tips for Use
As 90° Reflector
- Align the prism such that the beam passes through the input surface at the center and the incident beam is reflected back to retrace its path. The output beam shall be 90° to the input beam.
As 180° Reflector
- This configuration is used for folding the beam path as in binoculars.
- It also is used in beam inversion.
- The beam is made incident (at 0°) onto the hypotenuse, the beam gets reflected twice (from the sides) and comes out of the hypotenuse.