Topological photonic matter by optical Floquet driving

Temporal modulation of microcavity exciton-polariton condensates – a macroscopically coherent, hybrid state of cavity photons and quantum well excitons - can be used to controllably drive condensate dynamics and induce the formation of topological phases. Off-resonant driving by the interference of two GHz frequency-offset, structured lasers is used to demonstrate two distinct types of dynamics. Transverse dynamics are realized via an ‘optical stirrer’ which combines Laguerre-Gauss modes to rotate polariton condensates, leading to the nucleation and capture of multiple quantized vortices. Meanwhile, a one-dimensional, dynamical optical lattice is created by the use of two quasi-1D beams. Herein, the breaking of time-reversal symmetry causes the synthetic band structures to become non-reciprocal and acquire a universal tilt connected to the non-trivial topology of the Floquet–Bloch bands. Dynamical, incoherent manipulation via pump-induced reservoirs is shown to be a versatile method for driving dynamical states of polariton condensates and holds promise for the engineering of robust non-linear, topological phases of light.