Suppression of subsidiary fringes in white light interferometry utilizing two-wavelength light source

This paper analyzes and compares the two methods for suppressing the subsidiary fringes in white-light correlograms with two-wavelength light source. One of the methods adds the intensities of the two wavelength components and the other multiplies them. Peak intensity difference between the central fringe and the subsidiary fringes is investigated. A mathematical expression for a rapid estimation of the optimum wavelength difference between the two wavelengths is given for suppressing the subsidiary fringes. The effects of the intensities of the two wavelength components have also been investigated.