Spatial effect on the interference of light propagated in a film structure.

The interference of light has been analyzed for a film structure by considering that a spatial separation exists for the two neighboring light beams to be interfered in the space. There is a significant difference between the situations of the interference with or without consideration of the spatial effect, especially around the region where the phase delay delta=pi and 2pi by taking the example of the one-layered SiO2/Si structure. It is reasonable to extract the optical parameters by neglecting the spatial effect only for the thinner film with a thickness much smaller than a wavelength, which satisfies the condition that delta更多