Multiple beam interference with near-grazing waves in dielectric wedges: polarization dependence

Multiple beam interference of near-grazing waves has been recognized as responsible for bright interference patterns in dielectric wedges. Near-grazing waves are traveling waves having wave vectors forming an angle of nearly $\pi $/2 with the normal of a planar surface. When two such surfaces form a wedge with near-grazing waves within, two main features determine interference pattern formation. First, the values of the Fresnel reflection coefficients are close to unity for near-grazing waves. Second, the phase dependence as a function of the gap between surfaces is step-wise nearly constant for the same kind of waves. Both features have polarization dependence, so polarization dependence of interference patterns are also expected. Numerical results for $s$ and $p$ polarizations are presented under monochromatic and polychromatic illuminations. Experimental observations are also shown.