Ultrafast strain-induced switching of a bistable cavity-polariton system

In the reported experiment, a picosecond strain pulse induces a sharp transition between the steady states in a bistable cavity-polariton system. The strain pulse of 10-ps duration, generated in the GaAs substrate and injected into a high-Q GaAs/AlAs microcavity, modulates the exciton resonance energies of the embedded quantum wells and correspondingly of the polariton resonances. When the microcavity is pumped by a laser with the photon energy slightly above the lower-polariton resonance, the strain-induced energy shift triggers the irreversible switching of the bistable polariton system from the lower to the upper state. This transition is accompanied by an instant increase of the optical emission from the microcavity by more than an order of magnitude.