Polariton acceleration in a microcavity wedge

We report an experimental evidence of the acceleration of exciton-polaritons propagating in-plane of a semiconductor microcavity. The acceleration is achieved due to the gradient of the thickness of the cavity and results from the reciprocal space filtering effect of the cavity. The wave packet propagating in the cavity plane is constantly filtered by the cavity eigenmode that shifts towards larger wave vectors as the cavity width increases. The decay time of the emission of light by the propagating polaritons increases as one approaches the anticrossing region. We show that it is a consequence of the elastic scattering of the polaritons. The spatial size of propagating polariton packet decreases with time due to the same effect.