Polarization shaping of Poincaré beams by polariton oscillations

We propose theoretically and demonstrate experimentally the generation of light pulses whose polarization varies temporally to cover selected areas of the Poincare sphere with both tunable swirling speed and total duration (1 ps and 10 ps, respectively, in our implementation). The effect relies on the Rabi oscillations of two polariton polarized fields excited by two counter-polarized and delayed pulses. The superposition of the oscillating fields result in the precession of the Stokes vector of the emitted light while polariton lifetime imbalance results in its drift from a circle of controllable radius on the Poincare sphere to a single point at long times. The positioning of the initial circle and final point allows to engineer the type of polarization spanning, including a full sweeping of the Poincare sphere. The universality and simplicity of the scheme should allow for the deployment of time-varying full-Poincare polarization fields in a variety of platforms, timescales, and regimes. An international team has generated light pulses whose polarization varies in time over selected areas of the Poincare sphere. Beam shaping generally involves tailoring the phase and amplitude of a beam, but to fully exploit the vectorial nature of light it is desirable to extend this degree of control to polarization. Lorenzo Dominici and co-workers theoretically propose a new type of pulsed polarized light—one that adopts all polarization states during the pulse duration. They then demonstrate it experimentally in a semiconductor microcavity that has strong exciton–photon coupling. Since the mechanism is based on a ubiquitous effect of light–matter interactions, namely Rabi oscillations, it can be realized in both classical and quantum regimes as well as on various platforms and time scales. It can also be extended to non-optical systems.