Virtual-photon tunnel effect and quantum noise in a one-atom micromaser

M. L. Ladrón de Guevara, Miguel Orszag, R. Ramírez +1 more

E. S. Guerra, S. M. Dutra, P. L. Knight +1 more

We study degenerate two-photon micromasers pumped by cascade three-level atoms, where each atomic energy level has a different linewidth. Our model allows us to recover the ordinary two-photon micromaser situation when these widths vanish. In the limit of large linewidths we obtain a two-photon laser model. We show that trapping states are extremely sensitive to atomic decay, even when the decay time is small in comparison to the transit time through the cavity. Unlike the one-photon micromaser, they are sensitive to the linewidth of the upper, as well as the lower energy level. We have also studied the effects of atomic decay on the starting time of micromasers and on the noise. We found that there is a significant difference between the behavior of two-photon micromasers and lasers as we change the ratio of the widths of the upper and lower levels.

Zhengdong Liu, Liang Zeng, Shi‐Yao Zhu +1 more

In a one-atom micromaser, the expression for the density matrix of the cavity field without the rotating-wave approximation (RWA) is derived using a perturbation method. The phase evolution of the cavity field is investigated without the RWA, and the results are compared with those within the RWA. It is shown that the virtual-photon processes make the symmetric phase distribution in the RWA asymmetric and cause additional quantum oscillation, which indicate the field's phase fluctuation and frequency shift. Virtual photons also cause an extra phase distribution to the field which is initially in a vacuum state. The unique characteristic of the phase properties in the course of forming a photon-number state is investigated. Other new phenomena such as the undamped oscillation of the phase variance against the injected atomic number are found.

Miguel Orszag, J. C. Retamal

孙为辉, 杜四德, 陈效双

I Ashraf, A. H. Toor

We have developed a quantum theory of the micromaser for a pair of two-level atoms for the case of one- and two-photon transition coupling. We have studied the effect of co-operativity on the photon statistics for these systems for different coupling constant ratios. It is found that for equal coupling, our system of a two-atom, one-photon micromaser behaves like a double one-photon cascade micromaser. Similarly, for equal coupling, the photon statistics of the two-atom, two-photon micromaser reduces to that of a three-level, four-photon cascade micromaser.