Two=beam interferometer for measuring ultra precision surfaces - has mutually inclined partially mirrored surfaces bounding output vol, lens and aperture matched to partial beam pair for separation

摘要

The two-beam interferometer contains test object and partially reflecting reference surfaces and a monochromatic light source. Input, reference (R) and test (P) beams are used. The test beam is inclined w.r.t. the reference beam. Two partially mirrored surfaces (8,9) at an angle less than 1 Grad bound an output vol. Partial beam pairs are set up between the second partially mirrored surface and a lens (10). The width of an aperture (11) at the lens focal plane corresp. to the separation of the beam pair foci. USE/ADVANTAGE - For measuring surfaces machined with ultra precision. Improved measurement accuracy.