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 through the hypotenuse face parallel to the entering beam regardless of the orientation of the incident beam. For its special performance, it is often used to the distance measurement, optical signal process and laser interferometer.      

Specifications         

Material: BK7 Grade A Optical Glass  

Dimension Tolerance: +0.0, -0.2 mm     

Clear Aperture: >80%         

Deviation: 180°±3 arc sec     

Flatness: λ/4 @632.8 nm on big surface        

λ/10 @632.8 nm on other surface      

Surface Quality: 60-40 scratch and dig      

Wavefront Distortion: λ/2 @632.8       

Protective Bevel