polarise

Polarise (British spelling) or polarization (American spelling) is a term used in science, technology, and social discourse to describe processes that create or reveal polarity, as well as a result of such processes. The meanings share a core idea: the alignment or separation of contrasting properties.

In physics and optics, to polarise light means to restrict its oscillations to a particular orientation. Light can be polarised linearly, circularly, or elliptically. A polarising filter transmits only light with a chosen polarization, and various interactions, including reflection, refraction, birefringence, and scattering, can alter polarization states. Polarisation is also discussed in the context of electromagnetic waves in general and in optical instrumentation.

In materials science and chemistry, polarisation refers to the separation of electric charges within a material, creating an electric dipole moment. Dielectric polarisation occurs under an external electric field, while intrinsic polarisation can appear in ferroelectric or other polar materials. Molecular polarity arises from differences in electronegativity and affects properties such as solubility, reactivity, and intermolecular interactions.

In social and political contexts, polarisation describes the division of a population into opposing groups or camps, often with diminishing middle ground and intensifying conflict or strong attitudes. It is used to analyze trends in public opinion, elections, and policy debates.

In telecommunications and sensing, polarisation also denotes the orientation of the electric field of a signal or the design of devices that control or measure that orientation, such as antennas and polarising elements.

The terms polarisation and polarization are used interchangeably, depending on regional spelling conventions.