Polariton

In physics, polaritons /pəˈlærɪtɒnz, poʊ-/[1] are bosonic quasiparticles resulting from strong coupling of electromagnetic waves (photon) with an electric or magnetic dipole-carrying excitation (state) of solid or liquid matter (such as a phonon, plasmon, or an exciton).

That name was suggested by Solomon Isaakovich Pekar, but the term polariton, proposed by John Hopfield, was adopted.

[7] Room-temperature superfluidity of polaritons was observed in 2016 by Giovanni Lerario et al., at CNR NANOTEC Institute of Nanotechnology, using an organic microcavity supporting stable Frenkel exciton-polaritons at room temperature.

[9][10] In 2024 researchers reported ultrastrong coupling of the PEPI layer in a Fabry-Pérot microcavity consisting of two partially reflective mirrors.

Placing a PEPI layer within a Fabry-Pérot microcavity forms polaritons and allows control of exciton-exciton annihilation, increasing solar cell efficiency and ED intensity.

Dispersion relation of phonon polaritons in GaP . Red curves are the uncoupled phonon and photon dispersion relations, black curves are the result of coupling (from top to bottom: upper polariton, LO phonon, lower polariton).