Quantum theory of the micromaser with ultracold cascade three-level atoms:II. Spectral properties

We study the spectrum of the micromaser injected with ultracold cascade thr ee-level atoms. We examine the effects of the atomic centre-of-mass motion, the cavity length, the atom-field detuning, the ratio of the atomic inject ion rate to the cavity decay rate, and the number of photons in thermal equ ilibrium on the spectrum. We find that the micromaser injected with ultraco ld three-level atoms shows new spectral properties which are different from those of the micromaser injected with ultracold two-level atoms and the mi cromaser injected with thermal two- or three-level atoms. The main conclusi ons are that the linewidth can be broadened and the frequency can be either red-shifted or blue-shifted.