regime of CQED, as well as a useful effective model to describe solid-state emitters [10, 11]. Such a model has mostly been used to study the spectral properties of the light emitted by the atom-cavity system so far, especially with the aim of describing microphotoluminescence experiments performed on quantum dots coupled to semiconductor cavities [12–14]. In particular, pure dephasing has been identified as a potential mechanism for the so-called cavity feeding process [10, 11], namely the emission of photons at the cavity frequency that shows up even if the emitter is coupled to a detuned cavity mode [14–19]. This picture for artificial atoms in the solid state has shed new light on the effects of decoherence, which can be considered as a supplementary degree of freedom as compared to isolated atoms, offering appealing perspectives to achieve advanced nanophotonic devices controlled by pure dephasing [11]. Nevertheless, little attention has been paid to the dynamics of an emitter subject to pure dephasing and coupled to a cavity up to now. In this work, we consider the temporal evolution of the emitter’s and cavity mode populations, and show that the system in the incoherent regime can be described by a classical (rate-equation) model with an effective atom-cavity coupling rate. Such a coupling rate is a key parameter: it allows to define a generalized Purcell factor, and beyond, to revisit the notions of good and bad cavity regimes, respectively. We show that pure dephasing can increase the effective atom-cavity coupling, thus enhancing the effective Purcell factor of the system. Switching to the non-linear regime, we also show that the lasing properties of a single emitter can be evidenced by looking at the statistical properties of the emitted light, from which we characterize the conditions for the lasing onset to be achieved. In particular, we define parameters for which pure dephasing can even induce lasing, thus showing that decoherence can turn out to be an extremely positive resource in the framework of prospective solid-state nanophotonic devices. Within these framework, quantum dots appear as promising candidates, as the experimental strategies to tune their environment, thus the pure dephasing rate that controls their homogeneous linewidth, have already started to be developed. As a consequence, we have mostly used parameters consistent with state of the art experiments using quantum dots coupled to optical semi-conducting cavities. On top of it, we propose to implement a versatile device, that can be operated either as a single photon source or as a laser, based on the control of decoherence induced by the environment of the quantum dot. We also propose an innovative strategy to control this environment. 3