  Strong light-matter coupling is a quantum process in which light and matter
are coupled together, generating hybridized states. This is similar to the
notion of molecular hybridization, but one of the components is light. Here, we
utilized the idea and prepared quantum phototransistors using donor-acceptor
combinations that can transfer energy via Rabi oscillations. As a prototype
experiment, we used a cyanine J-aggregate (TDBC; donor) and MoS2 monolayer
(acceptor) in a field effect transistor cavity and studied the
photoresponsivity. The energy migrates through the newly formed polaritonic
ladder, and the relative efficiency of the device is nearly seven-fold at the
ON resonance. Further, the photon mixing fraction is calculated for each
independent device and correlated with energy transfer efficiency. In the
strongly coupled system, newly formed polaritonic states reshuffle the
probability function. A theoretical model based on the time dependent
Schr\"odinger equation is also used to interpret the results. Here, the
entangled light-matter states act as a strong channel for funnelling the energy
to the MoS2 monolayer, thereby boosting its ability to show the highest
photoresponsivity at ON-resonance. These experimental findings and the proposed
model suggest novel applications of strong light-matter coupling in quantum
materials.
