Diffraction management for grazing incidence interferometer

摘要

Test surfaces are measured at grazing incidence with an interferometer using diffractive optics for manipulating reference and test beams. A leading diffractive optic separates the reference and test beams, and a following diffractive optic recombines the beams after the test beam is reflected from the test surface. Extraneous light, including light from other orders of diffraction, is isolated and blocked from combining with test and reference wavefronts.