and for blue detuning experiences loss. This is completely consistent with the experimental observations in Fig. \[fano\]. When the gain of probe laser from atoms exceed the loss from the atoms-cavity system, we see lasing as shown in Fig. \[gainsim\](b) providing an explanation for the lasing of the red-detuned peak. In addition, the parameters in our calculations are such that $4|\Omega|^4 < |\Delta_{da}|^3\Gamma$ and $4|\Omega|^2 < |\Delta_{da}|^2$, where $2\Omega$ is Rabi frequency of the drive laser, $\Delta_{da}$ is detuning of drive laser from the atomic transition and $\Gamma$ is decay rate of the atomic excited state due to spontaneous emission. This is opposite to the conditions necessary for gain in probe beam according to [@grynberg_central_1993] and [@mollow_stimulated_1972] respectively, where the system was required to be driven hard. However, here the presence of cavity enhances the interaction, and we see gain even without the very demanding requirements on parameters in the earlier experiments.

![Probe transmission through the cavity as a function of detuning from the atomic transition. Blue is empty cavity transmission, the dotted brown curve is the VRS and red dashed curve shows probe transmission when atoms are driven by classical light. The two graphs are for different detuning of 