Squeezed state generation by the normal mode splitting of two-level atoms in an optical cavity

In recent years there has developed a rapidly growing interest in the manifestly quantum or nonclassical features of the electromagnetic field. From the perspective of quantum optics, such nonclassical features are of great intrinsic interest; however, a widening audience is now being attracted to problems in this area because of potential applications to measurement science, to optical communication, and to atomic spectroscopy. Squeezed states of the electromagnetic field are one example of quantum states that are the subject of intense activity, with several observations of squeezing now having been reported. In at least one case, a sufficient degree of squeezing to warrant serious attention to possible application has been demonstrated. Squeezing refers to the phase dependent redistribution of the quantum fluctuations of the field such that the variance in one of two orthogonal quadrature operators drops below the level of fluctuations set by the vacuum state of the field (the zero-point level).