Patent ID: 8174769

Claim:
A beamsplitter comprising: a plate having two approximately parallel and opposing planar surfaces and a partially reflective layer coating at least one of the planar surfaces; a first mounting system configured to support and position the plate; a compensator plate having two approximately parallel and opposing planar surfaces; and a second mounting system configured to support and position the compensator plate, wherein at least one of the first mounting system and the second mounting system position the plate and the compensator plate so that an incident beam of light passing through the compensator plate acquires a first beam offset, and the incident beam of light with the first beam offset passing through the plate is split into a reflected beam of light and a transmitted beam of light by the partially reflective layer where the transmitted beam of light has a second beam offset that substantially cancels the first beam offset such that the transmitted beam of light is approximately parallel to and aligned with the incident beam of light.