Physical Review A
Polarization switching in an anisotropic cavity coherently pumped J=1→J′=0 laser
Carles Serrat, Ramon A. Vilaseca, Germán J. de Valcárcel, Eugenio Roldán
Abstract
We show that, in an optically pumped resonant $J=1\ensuremath{\rightarrow}{J}^{\ensuremath{'}}=0$ laser, a gain anisotropy is induced by a linearly polarized coherent pump beam that can be balanced or countered by $x$-$y$ cavity-loss anisotropies, leading to switching between the $x$ and $y$ linearly polarized states of the generated laser field as the laser intensity is increased. This switching is not brought about by selection of the mode with the maximum emission intensity. A domain of bistability between the two linearly polarized states is found, whose width depends on the value of the decay rate of the two photon coherence induced among the sublevels of the $J=1$ level manifold. Differently from the incoherently pumped $J=1\ensuremath{\rightarrow}{J}^{\ensuremath{'}}=0$ laser, the decay rate for the magnetic dipole in that manifold has no influence on the polarization of the emission.