White‐light scanner (WLS)

A device for measuring the physical geometrical characteristics of an object using white‐light interferometry. WLS systems capture intensity data at a series of positions along the vertical axis, determining where the surface is located by using the shape of the white‐light interferogram, the localized phase of the interferogram, or a combination of both shape and phase. The white‐light interferogram consists of the superposition of fringes generated by multiple wavelengths, obtaining peak fringe contrast as a function of scan position; the red portion of the object beam interferes with the red portion of the reference beam; the blue interferes with the blue, and so forth. A prodigious amount of data is available in a white‐light interferogram.