  Achieving electrical injection of exciton-polaritons, half-light, half-matter
quasiparticles arising from the strong coupling between photonic and excitonic
resonances, is a crucial milestone to scale up polaritonic devices such as
optical computers, quantum simulators and inversionless lasers. Here we present
a new approach to achieve strong coupling between electrically injected
excitons and photonic bound states in the continuum of a dielectric metasurface
monolithically patterned in the channel of a light-emitting transistor.
Exciton-polaritons are generated by coupling electrically injected excitons in
the gate-induced transport channel with a Bloch mode of the metasurface, and
decay into photons emitted from the top surface of the transistor. Thanks to
the high-finesse of the metasurface cavity, we achieve a large Rabi splitting
of ~200 meV and more than 50-fold enhancement of the polaritonic emission over
the intrinsic excitonic emission of the perovskite film. Moreover, we show that
the directionality of polaritonic electroluminescence can be dynamically tuned
by varying the source-drain bias which controls the radiative recombination
zone of the excitons. We argue that this approach provides a new platform to
study strong light-matter interaction in dispersion engineered photonic
cavities under electrical injection, and paves the way to solution-processed
electrically pumped polariton lasers.
