Multi-axis interferometer with integrated optical structure and method for manufacturing rhomboid assemblies

A manufacturing method for rhomboid assemblies cuts stacks of glass plates that are glued together with coatings between the glass plates. The cuts are at an angle such as 45° and surfaces resulting from the cuts are finished to optical tolerances. These optical surfaces permit attachment of rhomboid assemblies directly to optical elements such as a polarizing beam-splitter (PBS) in a multi-axis interferometer. Further, elements such as quarter-wave plates, cube corner reflectors, and rhomboid elements that extend the separation of measurement beams can be attached to the PBS to provide integrated beam optics that are compact and thermally stable. Placing a reflective coating or other reference reflector on a quarter-wave plate for the reference beam can keep the entire beam path for the reference beam within the integrated structure. When rhomboid elements extend the separation between measurement beams, an extension to the PBS can match the optical path lengths of reference and measurement beams.