View source for Photon polarization

'''Photon polarization''' is the quantum mechanical property of a photon that describes the orientation of its electric field oscillation. In the context of [[quantum communication]], polarization is the most commonly used degree of freedom for encoding quantum bits because it is relatively easy to manipulate and measure with standard optical components.

A photon can be prepared in states of linear polarization (horizontal, vertical, or diagonal) or circular polarization. The non-commutativity of different polarization bases — rectilinear versus diagonal, for instance — is the operational basis of the [[BB84 Protocol|BB84 protocol]] and other [[Quantum Key Distribution|quantum key distribution]] schemes. Any attempt to measure a photon in a basis different from its preparation basis destroys the original state information, a manifestation of the [[Uncertainty Principle|uncertainty principle]] at the level of single quanta.

The fragility of polarization states in optical fiber — due to birefringence and environmental perturbations — is one of the principal engineering challenges in implementing [[Quantum Communication|quantum communication]] over long distances.

[[Category:Physics]] [[Category:Quantum Mechanics]]