Abstract

Strong coupling in semiconductor microcavities gives rise to hybrid light-matter particles, polaritons. It has been widely demonstrated that polaritons can undergo a phase transition and condense in the ground state of the system [1]. Moreover it has been shown that the polariton energy landscape can be optically molded [2, 3] due to the repulsive exciton-polariton interactions that dominate in the area of an optical pump spot. We report on high order Hermite-Gaussian modes of a polariton condensate in an optically generated annular trap. Optically confined polariton condensates have been shown to have improved coherence features as they do not suffer from depletion and dephasing processes associated with the interaction of polaritons with the exciton reservoir [4]. Increasing the trap size and therefore reshaping the trapping potential leads to condensation in multi-lobe symmetric and asymmetric higher-order modes that can extend over 60μm (Fig.1). The incoherent polariton gas in the optical trap, upon reaching a threshold density, condenses in a pure quantum state, determined by the geometric shape of the excitation [5]. We demonstrate that the preferential energy state for condensation is always the highest energy state of the trap with the greatest wavefunction overlap to the feeding reservoir.

© 2015 IEEE