Superradiance enhancement by bad-cavity resonator

In this work we consider the dynamics of an ensemble of two-level atoms that interact with finite-width resonator mode. The superradiant burst occurs under a wide range of parameters in such a system. However, if the initial phase distribution of dipole moments of N two-level atoms is random, not all atoms take part in the superradiant process, but only the part of them that results in the intensity of supperradiance $I\sim N^{\alpha }$, where $\alpha <2$. In this paper we investigate the dependence of the parameter α on the resonator mode decay rate. It is shown that there is a critical value of resonator mode decay rate that divides two different regimes of superradiance. If the decay rate is lower than the critical rate, superradiance demonstrates a multi-peak character and the number of dipoles forming superradiant burst increases while α grows from 1 to 2. When the decay rate is larger than the critical value there is a single-peak superradiant regime. The delay time dependence on N changes from power to logarithmic law at the critical decay rate. The existence of the optimal value of resonator decay rate can be used for superradiance enhancement by a resonator with finite losses. (paper)