Ppolarization

P-polarization, commonly written as p-polarization, refers to the polarization state of an electromagnetic wave in which the electric field lies in the plane formed by the incident wave vector and the normal to an interface (the plane of incidence). This is in contrast to s-polarization, where the electric field is perpendicular to that plane. When light encounters a boundary between two media, the behavior of the p-polarized component is described by the Fresnel equations, which give separate reflection and transmission coefficients for p- and s-polarized light.

The reflectance and transmittance of p-polarized light depend on the angle of incidence and the refractive indices of the two media. As the angle changes, the amplitudes of the reflected and transmitted p-polarized waves vary according to the TM (transverse magnetic) form of the Fresnel equations. At certain angles, notable effects occur, such as the existence of a Brewster angle, at which the reflectivity for p-polarized light becomes zero when light is incident from medium 1 into medium 2. This angle satisfies tan(theta_B) = n2/n1, where n1 and n2 are the refractive indices of the two media.

P-polarization is widely used in optics and photonics. Polarizers and anti-reflection coatings often exploit the distinct behavior of p-polarized light at interfaces to control reflection, transmission, and phase. In analytical techniques such as ellipsometry, changes in the p-polarized component upon reflection provide information about thin films and surface properties. The concept is also incorporated into polarization optics, interference coatings, and the study of light-murface interactions.