Boundary effects on the dynamics of exciton polaritons in semiconductor microcavities

Using the coupled Gross-Pitaevskii equations, we investigate the boundary effects on the dynamics of exciton polaritons in semiconductor microcavities excited by an applied vertical pump field. As the radius of the Gaussian pump field is far larger than a critical value, the boundaries of semiconductor microcavities will strongly enhance the anisotropy of the polariton-polariton scattering, and thus the polarization dependence of the polariton-polariton scattering can be neglected. Moreover, the pump threshold behavior of the anisotropy in the polariton-polariton scattering can be avoided by introducing fixed boundary conditions. In the low excitation regime, such an enhancement of anisotropy can be used to generate a pair of nearly intensity-symmetric correlated polaritons, and this efficacy can be more easily achieved by using square microcavities with small area.