Manifestation of effects of the angular spectrum of the illuminating field in polychromatic interference microscopy of stratified objects

An effect of the angular spectrum width of a polychromatic illuminating field on the interference pattern color in optical microscopy of stratified objects is considered. Equations describing the intensity of interference patterns of thin stratified objects are obtained with due account for the influence of both frequency and angular spectra of the illuminating field. The angular spectrum width of the illuminating field is shown to affect the mutual coherence and phase difference of the interfering fields. Computer-simulated interference patterns for a thin layer under monochromatic and polychromatic illumination with different widths of the angular spectrum are presented. Quantitative analysis of the effect of angular aperture of white light on the colors of the resulting interference pattern is carried out. Changes in the colors of the layer interference patterns are experimentally studied when changing the width of the angular spectrum of the illuminating field. Color variations of the interference patterns obtained experimentally and theoretically are compared.