It has three mutually perpendicular surfaces and a hypotenuse face, light entering through the hypotenuse is reflected by each of the three surfaces in turn and will emerge though the hypotenuse face parallel to the entering beam regardless of the orientation the incident beam, it is often used to the distance measurement, optical signal process and laser interferometer.
Application:
- geodetic measurement instrument
- precision measurement in laboratory
- Astronautics and Aviation
