Dynamic compression of exciton-polariton condensates in semiconductor microcavities

The possibility of the dynamic compression of a polariton system in a planar microcavity after the end of a resonant pump pulse with the formation of the ground state of a condensate on the bottom of the polariton band has been studied. The studies of dynamics of a resonantly excited polariton gas in the mean field approximation have shown that such condensate state can be formed purely dynamically at excitation by coherent convergent Gaussian light pulses with a large aperture if the active region of the cavity is ahead of the waist of the Gaussian beam. The spatial distribution of polaritons in the formed high-density condensate has sharp edges and large jumps of the violet shift and quasimomentum on these edges prevent its monotonic expansion despite the repulsive interaction between polaritons. For this reason, the further evolution of the condensate is primarily due to the discharge of particles from its boundary and is accompanied by a decrease rather than an increase in the size of the high-density region at the initial stage. Thus, the self-sustained regime of the dynamic compression of the polariton condensate can be maintained for a relatively long time.