Fringe beating effects induced by misalignment in a white-light interferometer

The profile of the interference fringe packet obtained in interferometry, especially in the topical area of white-light interferometry, may be dramatically altered by the presence of the so-called 'fringe beating effect' due to the poor quality of the collimation lens or the misalignment of the optical arrangement. In the worst cases, the peak value of the central fringe will be equal to or even less than that of the other fringes and in consequence will give an erroneous result for the determination of the central fringe position in the visibility profile. This effect is considered using a simple computer simulation model and the results both from the computer simulation and from experiment are discussed and compared to find means of eliminating such effects.