Wedge Window

Wedge windows 

They are often used to deflect the incident beam to the direction at a certain deflection angle. When used in pairs, the outgoing beam can be positioned in any direction within a pyramid with the incident beam as the axis through the relative rotation of the two optical wedges. 

The high-precision wedge-shaped window can avoid the interference effect (Etalon effect) caused by the reflected light from the front and rear surfaces of the high-parallelism window, and can also avoid the poor stability of laser output and mode jumping caused by the optical interference feedback of the laser resonator.