Design And Experimental Study Of Partial Coherent Microscope

The partially coherent interference microscope which combine partially coherent light interferometry and microscopy imaging technology has an irreplaceable role in the microscopic surface topography measurement, compared with monochromatic laser interferometry, it can not only solve the problem of phase ambiguity, but also able to measurement of surface roughness by microscopic enlarge. Compared with the traditional contact measurement methods, it has a series of advantages, like fast, non-contact, high accuracy, over the years has attracted much attention and research.This paper describes the partially coherent light interference principle, discusses three common interference microscope objective structures, and gives a detailed derivation of the three interference microscope models. Focus on the optical structure design of interference microscope, proposes design requirements and solutions for imaging optics, illumination optical path and intensity matching, including the selection of microscopic structure of the system, choice the structure of the interference microscope objective, lens design and optimization, selection and design the way of illumination, and the problem of intensity matching. The article also studies the dispersion problem against interference microscope, discusses the causes of dispersion and the impacts it may cause to the interference fringes, and put the numerical aperture into account, deduces the expression of intensity on the basis of the interference microscopic model, by the simulation results demonstrate the impacts of dispersion for different numerical apertures on the interference fringes. Finally, analysis the problem of fringe contrast poorly in the actual measurement system, and measures residual aberrations of the system and surface of the spectral flat, and discusses the impact of residual aberrations on interference fringes.