  Electro-optic control of quantum dots embedded in the plasmonic nanocavities
enables active tuning of photonic devices for emerging applications in Quantum
optics such as quantum information processing, entanglement and ultrafast
optical switching. Here, we demonstrate the coherent control of plexcitonic
states in (i) an off-resonant and (ii) a resonant coupled quantum systems
through optical Stark effect (OSE). We analyze a hybrid plasmon-emitter system
which exhibits tunable Fano resonance, Stark induced transparency (SIT) and
vacuum Rabi splitting due to quadratic Stark shift in the degenerate states of
quantum emitter (QE). In addition, a resonantly coupled system shows the
signature of double Fano resonance due to Stark-induced splitting in a
two-level QE. Our study shows that Stark tuning of plexcitons not only
mitigates decoherence in the quantum system but it also stimulates on/off
switching of spontaneous photon emission in the visible regime. Such tunable
systems can be used to operate photonic integrated circuits (PIC) for
applications in quantum computing and information processing.
