Selective photoexcitation of confined exciton-polariton vortices

Abstract

We resonantly excite exciton-polariton states confined in cylindrical traps. Using a homodyne detection setup, we are able to image the phase and amplitude of the confined polariton states. We evidence the excitation of vortex states, carrying an integer angular orbital momentum $m$, analogous to the transverse $TE{M}_{{01}^{\ensuremath{\ast}}}$ ``donut'' mode of cylindrically symmetric optical resonators. Tuning the excitation conditions allows us to select the charge of the vortex. In this way, the injection of singly charged $(m=1\text{ }\text{and}\text{ }m=\ensuremath{-}1)$ and doubly charged $(m=2)$ polariton vortices is shown. This work demonstrates the potential of in-plane confinement coupled with selective excitation for the topological tailoring of polariton wave functions.