Controllable structuring of exciton-polariton condensates in cylindrical pillar microcavities

TL;DR

This paper demonstrates controllable formation of exciton-polariton condensates in cylindrical microcavities, showing how their spatial structure can be manipulated by excitation position and intensity, with implications for quantum state engineering.

Contribution

It introduces a method to control exciton-polariton condensate structures in microcavities through excitation parameters and develops a theoretical model describing these out-of-equilibrium states.

Findings

Condensation occurs in concentric rings with controllable number.

Breaking symmetry transforms rings into lobes with nonzero angular momentum.

Theoretical model matches experimental observations.

Abstract

We observe condensation of exciton polaritons in quantum states composed of concentric rings when exciting cylindrical pillar GaAs/AlGaAs microcavities non-resonantly by a focused laser beam normally incident at the center of the pillar. The number of rings depends on the pumping intensity and the pillar size, and may achieve 5 in the pillar of 40 mkm diameter. Breaking the axial symmetry when moving the excitation spot away from the pillar center leads to transformation of the rings into a number of bright lobes corresponding to quantum states with nonzero angular momenta. The number of lobes, their shape and location are dependent on the spot position. We describe the out-of-equilibrium condensation of polaritons in the states with different principal quantum numbers and angular momenta with a formalism based on Boltzmann-Gross-Pitaevskii equations accounting for repulsion of polaritons from the exciton reservoir formed at the excitation spot and their spatial confinement by the pillar boundary.