Switching in polaritonic-photonic crystal nanofibers doped with quantum dots.

We have studied the acousto-optic effect in polaritonic nanofibers made by embedding a cylindrical polaritonic nanowire within a photonic crystal. Here the nanowire consists of either a phonon-polaritonic or an exciton-polaritonic material. The nanowire is doped with ensemble of noninteracting quantum dots. Quantum dots interact with the nanofiber via the exciton-polariton interaction. It is found that for the certain acoustic strain intensity the nanofiber has a localized-to-delocalized polariton transition similar to the metal-to-insulator transitions in doped semiconductors. It is also found that nanofiber has a transparent state due to the exciton-bound polariton coupling. The transparent state can be switched ON or OFF by the external acoustic strain intensity. These are very useful discoveries that can be used to fabricate new types of polaritonic nanoswitches and nanosensors.