Properties of steady-state field in micromaser pumped by atoms in superposition of their upper and lower states

Fam Le Kien

Pierre Meystre, John J. Slosser, Ewan M. Wright

John J. Slosser, Pierre Meystre, Ewan M. Wright

At low temperatures steady-state macroscopic superpositions can be generated in the field of a micromaser pumped by a stream of two-level atoms injected in a coherent superposition of their upper and lower states. The onset of these superpositions resembles a second-order phase transition, with the control parameter being the ratio of the atomic injection rate to the cavity damping rate.

Shahid Qamar

We present a study on the quantum statistical properties of radiation in a one-photon micromaser. In particular, the possibility of generating steady-state squeezing is investigated. The spectral properties of the radiation field in a micromaser are also studied. \n \nWe show that the steady-state squeezing can be generated in a lossless micromaser by injecting the atoms in a coherent superposition of upper and lower states. It is shown by considering initial vacuum number and thermal state of the cavity field, that for a particular choice of the interaction time field evolves to a squeezed state. Steady- state squeezing is found to be independent of the initial state of the cavity field. However, the temporal evolution of the squeezing depends on the initial state of the field. Effects of cavity losses and pump fluctuations on steady-state squeezing are also investigated. \n \nFinally, an exact analytic expression for the linewidth of a micromaser in the absence of cavity losses is obtained by evaluating the two-time correlation function. A comparison with the natural linewidth of laser shows that under certain conditions gain contribution to the linewidth is same in both the cases. We also, derive an exact expression for the phoston distribution function and show that for a particular choice of the interaction time, the number state of the field can be generated.

Jozef Škvarček, Mark S. Hillery

We present a semiclassical method for determining the phase distribution and the average photon number of a steady-state micromaser field pumped by a stream of resonant two-level atoms in a superposition of their upper and lower states. Assuming the field to have a photon number distribution with a single sharp peak, we find an equation for the amplitude and the phase of the steady-state field, which has two solutions. The stability analysis shows which one of the two is physically realizable. Using the very simple time evolution of particular atomic states, valid in the semiclassical limit, we find an expression for the phase distribution of the field that contains the mean photon number as a parameter. That can be determined from the stable solution.

Mudassar Aqueel Ahmad, Naveed Iqbal, Shahid Qamar