Time-Delay Polaritonics

Non-linearity and finite signal propagation speeds are omnipresent in nature, technologies, and real-world problems, where efficient ways of describing and predicting the effects of these elements are in high demand. Advances in engineering condensed matter systems, such as lattices of trapped condensates, have enabled studies on non-linear effects in many-body systems where exchange of particles between lattice nodes is effectively instantaneous. Here, we demonstrate a regime of macroscopic matter-wave systems, in which ballistically expanding condensates of microcavity exciton-polaritons act as picosecond, microscale non-linear oscillators subject to time-delayed interaction. The ease of optical control and readout of polariton condensates enables us to explore the phase space of two interacting condensates up to macroscopic distances highlighting its potential in extended configurations. We demonstrate deterministic tuning of the coupled-condensate system between fixed point and limit cycle regimes, which is fully reproduced by time-delayed coupled equations of motion similar to the Lang-Kobayashi equation

Data for Synthetic band-structure engineering in polariton crystals with non-Hermitian topological phases

Experimental data and numerical simulation results used to create the figures in the paper Pickup, L., Sigurdsson, H., Ruostekoski, J. &amp; Lagoudakis, P. (2020) Synthetic band-structure engineering in polariton crystals with non-Hermitian topological phases. Nature Communications.</span

Data for: Polariton spin jets through optical control

Experimental data and simulation results used to create the figures in the paper: Pickup, L., T&ouml;pfer, J.D., Sigurdsson, H. &amp; Lagoudakis, P. G. (2021) Polariton spin jets through optical control. Physical Review B.</span

Next-nearest-neighbor coupling with spinor polariton condensates

We report on experimental observation of next-nearest-neighbor coupling between ballistically expanding spinor exciton-polariton condensates in a planar semiconductor microcavity. All-optical control over the coupling strength between neighboring condensates is demonstrated through distance-periodic pseudospin screening of their ballistic particle outflow due to the inherent splitting of the planar cavity transverse-electric and transverse-magnetic modes. By screening the nearest-neighbor coupling we overcome the conventional spatial coupling hierarchy between condensates. This offers a promising route toward creating unconventional nonplanar many-body Hamiltonians using networks of ballistically expanding spinor exciton-polariton condensates

Data for Time-Delay Polaritonics

Experimental data and numerical simulation results used to create the figures in the paper T&ouml;pfer, J.D., Sigurdsson, H., Pickup, L. &amp; Lagoudakis, P. (2019). Time-Delay Polaritonics. Communications Physics.</span

Persistent self-induced Larmor precession evidenced through periodic revivals of coherence

Interferometric measurements of an optically trapped exciton-polariton condensate reveal a regime where the condensate pseudo-spin precesses persistently within the driving optical pulse. For a single 20 microsecond optical pulse the condensate pseudo-spin undergoes over 100000 full precessions with striking frequency stability. The emergence of the precession is traced to polariton non-linear interactions, that give rise to a self-induced out-of-plane magnetic field, which in turn drives the system spin dynamics. The Larmor precession frequency and trajectory is directly influenced by the condensate density, enabling the control of this effect with optical means. Our results accentuate the system's potential for the realization of magnetometry devices and can lead to the emergence of spin-squeezed polariton condensates

Data to support the article &quot;Persistent self-induced Larmor precession evidenced through periodic revivals of coherence&quot;

Data from experimental measurements and numerical simulations used to create the figures in the paper Sigurdsson, H., Gnusov, I., Alyatkin, S., Pickup, L., Gippius, N.A., Lagoudakis, P.G. &amp; Askitopoulos, A. (2022) &quot;Persistent self-induced Larmor precession evidenced through periodic revivals of coherence&quot; in Physical Review Letters.</span

Optical bistability under nonresonant excitation in spinor polariton condensates

We realise bistability in the spinor of polariton condensates under non-resonant optical excitation and in the absence of biasing external fields. Numerical modelling of the system using the GinzburgLandau equation with an internal Josephson coupling between the two spin components of the condensate qualitatively describes the experimental observations. We demonstrate that polariton spin bistability strongly depends on the condensate’s overlap with the exciton reservoir by tuning the excitation geometry and sample temperature. We obtain non-collapsing bistability hysteresis loops for a record range of sweep times, [10µs, 1s], offering a promising route to spin switches and spin memory elements.<br/

Data for Optical bistability under non-resonant excitation in spinor polariton condensates

Experimental data and numerical simulation results used to create the figures in the paper Pickup, L., Kalinin, K., Askitopoulos, A. M., Hatzopoulos, Z., Savvidis, P. G., Berloff, N. G., &amp; Lagoudakis, P. (2018). Optical bistability under nonresonant excitation in spinor polariton condensates. Physical Review Letters. </span