INFLUENCE OF SPONTANEOUS EMISSION ON TRAPPING STATES AND START-UP TIMES OF DEGENERATE 2-PHOTON MICROMASERS

We study degenerate two-photon micromasers pumped by cascade three-lev el atoms, where each atomic energy level has a different linewidth. Ou r model allows us to recover the ordinary two-photon micromaser situat ion when these widths vanish. In the limit of large linewidths we obta in a two-photon laser model. We show that trapping states are extremel y sensitive to atomic decay, even when the decay time is small in comp arison to the transit time through the cavity. Unlike the one-photon m icromaser, they are sensitive to the linewidth of the upper as well as the lower energy level. We have also studied the effects of atomic de cay on the starting time of micromasers and on the noise. We found tha t there is a significant difference between the behavior of two-photon micromasers and lasers as we change the ratio of the widths of the up per and lower levels.