Quantum island states in the micromaser

Publisher Website
Google Scholar
Abstract
We study the photon statistics of a micromaser with a nonzero thermal background for a large range of the pumping parameter θ. The photon statistics are examined in a two-dimensional space, parametrized by θ and k, where k is the photon number. For values of θ which are not too large, there are prominent peaks in the photon-number distribution. The locations of these peaks are determined by well-defined structures in θ-k space. These structures lie along curves in this space. As θ is increased, these structures disappear and the number distribution becomes diffuse. When θ becomes sufficiently large, however, new structures which are well localized in θ and k appear. We call these states ‘‘island states.’’ These states exhibit a strong squeezing of the photon number and are fairly insensitive to the thermal background. Their noise increases slowly due to fluctuations of the atomic beam as long as the spread in values of the pump parameter θ is smaller than the distance between the islands. Bistable behavior can be induced by fluctuations that overlap adjacent island states. We also present the photon statistics of a micromaser pumped by atoms in a mixture (incoherent superposition) of their upper and lower levels. It is shown that the noise in island states can be drastically reduced by an optimum amount of injected absorption. These features render these states experimentally feasible, so that they could be used for generating squeezed quantum states of the radiation field that are well localized in θ and k.