Operation speed of polariton condensate switches gated by excitons

Abstract

We present a time-resolved photoluminescence (PL) study in real and momentum space of a polariton condensate switch in a quasi-one-dimensional semiconductor microcavity. The polariton flow across the ridge is gated by excitons inducing a barrier potential due to repulsive interactions. A study of the device operation dependence on the power of the pulsed gate beam obtains a satisfactory compromise for the on-off signal ratio and switching time of the order of 0.3 and $\ensuremath{\sim}50$ ps, respectively. The opposite transition is governed by the long-lived gate excitons, consequently, the off-on switching time is $\ensuremath{\sim}200$ ps, limiting the overall operation speed of the device to $\ensuremath{\sim}3$ GHz. The experimental results are compared to numerical simulations based on a generalized Gross-Pitaevskii equation, taking into account incoherent pumping, decay, and energy relaxation within the condensate.