SQUEEZING IN THE OUTPUT OF A HIGH-GAIN ATOMIC LIGHT AMPLIFIER

In studying the amplification of squeezed light by a linear atomic light amplifier, various authors have found that the output light will not be squeezed for intensity gains greater than a limiting value of 2. In this paper we examine the general conditions under which this limiting value is applicable and find that for the atomic light amplifier it is associated with the vanishing of the initial average coherence of the atoms. A multi-stage atomic light amplifier is discussed, in which the atoms are in specially prepared initial states, which allows in principle a squeezed output for any value of the gain.