Localized cavity polaritons supported by the exciton field discontinuities

In this work, a novel type of localized bright solitons, existing due to intrinsic bistability of the system allowing spatial discontinuities in exciton field is reported. Neglecting pump and damping, the dispersion of stationary linear polaritons consists of two branches. Apart from regions of the lower branch with large |k|, the diffraction of polaritons is normal, and thus it can not be compensated by defocusing type nonlinearity caused by exciton repulsive interaction. As a result, usual bright solitons do not exist for small to moderate k´s. However it was found that formation of specific bright solitons supported by discontinuities in exciton field is possible for pump frequencies inside the gap between two polariton branches. This paper presents examples of simple one-dimensional localized excitation. . These localized excitations form families of solutions with the width being a continuous parameter ranging from zero to the maximum value defined by the system parameters and pump frequency. Importantly, it was found that such excitations survive as stationary localized solutions in presence of week exciton diffraction, thus making it possible to observe localization in real physical setups.