Threshold and non-linear behavior of lasers of Λ\Lambda and V - configurations

Dynamic properties of closed three level laser systems are investigated. Two schemes of pumping - $\Lambda$ and V - are considered. It is shown that the non-linear behavior of the photon number as a function of pump both near and far above threshold is crucially different for these two configurations. In particular, it is found that in the high pump regime laser can turn off in a phase-transition-like manner in both $\Lambda$ and V schemes.Comment: 9 pages, 5 figure

Double dressing by both the number of atoms and the number of photons inside cavity

We study a system of N two-level atoms interacting with a coherent field a resonant cavity in a self-consistent manner. No direct correlation between the atoms, such as induced by dipole–dipole interaction, is included. Initially all atoms are not exited, and there are n0 photons in the cavity. We show that the system reveals collective-like behavior, which stems from mutual influence of the atoms and coherent field in the cavity. In distinction from conventional dressing of atomic states by strong electromagnetic field, the system of N two-level atoms in a resonant cavity is actually dressed by both the number of photons and the number of atoms N. This double dressing results in both N and n0-dependent oscillation frequency, ω(n0,N). At N>>n0 the spectral density contains, apart from the main peak at the collective atomic frequency gN, additional features at odd sub-harmonics. There is interference signature at the double dressing spectrum which has half-peaks and half-dips that is a synchronization among the frequencies of photon and the atomic dressings. It is a beautiful manifestation of quantum interference in the present novel double dressing by the number n of photons and by the number N of atoms