THEORY OF THE 2-PHOTON MICROMASER - LINEWIDTH

In this paper, we study the linewidth of a two-photon micromaser by us ing an exact Hamiltonian approach. We consider a three-level atomic sy stem interacting with a single-mode radiation field. The intermediate level is considered to be off resonant with the field. In this model, under the large detuning limit, two-photon transitions result. We calc ulate the linewidth of a two-photon micromaser and present results in the small and large detuning limits. In the small detuning limit, sing le-photon behavior is evident, whereas in the large detuning limit, tr ue two-photon behavior is exhibited. We compare the results for the li newidth, under a large detuning limit, with the results obtained by us ing a phenomenological, effective Hamiltonian approach. The absence of the dynamic Stark shift in a phenomenological, effective Hamiltonian leads to qualitatively different results in the two approaches.