Squeezed states of light

Techniques for analytically characterizing squeezed states of light, as well as defining their properties, producing them and applying the phenomenon are presented. Squeezed light is an example of a nonclassical light field, i.e., it has no positive singular nonsingular Glauber-Sudarshan P function. The squeezed states exhibit less zero-point fluctuations in one quadrature than predicted by the Heisenberg uncertainty relation, while simultaneously experiencing increased fluctuations in the other quadrature. Phase dependent correlation functions can be used to predict the variance in the individual quadratures. The Wigner, Q, and the generalized P functions are employed to mathematically express the squeezed states, which have not been produced experimentally. Heterodyne and homodyne techniques for detecting the squeezed states are discussed, as are applications of the states in optical communications systems.