Emission from driven atoms in collective strong coupling with an optical cavity

Abstract: We study self sustained cavity emission from driven atoms in collective strong coupling. The cavity emission occurs over a wide range of atom-cavity and drive laser detunings without any external input to the cavity mode. Second order correlation measurements ($g^2(\tau)$), further reveal unanticipated phenomenon in the observed cavity emission such as, (a) damped oscillations at two frequencies and (b) significantly distinct $g^2(\tau)$ for different polarization components. The intricate relation between cavity emission intensity, drive laser detuning and atom-cavity detunings is explained. A possible mechanism for the damped oscillations with two frequency components in $g^2(\tau)$ is suggested. Measurements show the existence of two separate polarization decoupled mechanisms with distinct photon statistics, through which energy is transferred from the drive field to the cavity field. The statistical properties and mechanisms underlying cavity emission, as presented in this work, are expected to provide valuable insights for extending non-destructive detection techniques to the regime of collective strong coupling.