Pyöreäpolarisaatio

Pyöreäpolarisaatio is a term used in physics, specifically in optics and electromagnetism, to describe a type of electromagnetic wave, such as light, where the electric field vector rotates in a circular path as the wave propagates. This is in contrast to linear polarization, where the electric field oscillates along a single straight line, or elliptical polarization, where the electric field vector traces an elliptical path.

There are two types of circular polarization: right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP). The direction of rotation is determined by the relative phase difference between two orthogonal components of the electric field. For perfect circular polarization, these components must have equal amplitude and a phase difference of 90 degrees (or pi/2 radians).

Circularly polarized light can be created by passing linearly polarized light through a quarter-wave plate. Conversely, circularly polarized light can be converted into linearly polarized light using a similar optical element.

This phenomenon has various practical applications. For instance, it is used in 3D movie systems to separate the images meant for the left and right eyes, where each eye receives light with opposite circular polarization. It is also employed in satellite communications and radar systems to reduce interference and signal loss, particularly when reflections from surfaces can alter the polarization state of the wave. The ability to distinguish between RHCP and LHCP is crucial in these applications.