All-Optical Linear-Polarization Engineering in Single and Coupled Exciton-Polariton Condensates

Abstract

We demonstrate all-optical linear polarization control in semiconductor microcavities using an exciton-polariton condensate in an elliptically shaped optical trap. The microcavity inherent TE-TM splitting lifts the pseudospin degeneracy of the anisotropic trap ground state. The emerging fine structure modes are shown to be polarized linearly parallel and perpendicular to the trap major axis. We demonstrate polariton condensation into the excited pseudospin mode with high degree of linear polarization which rotates as we rotate the trap. We then extend our study to a system of two coupled linearly polarized condensates and demonstrate rich spin dynamics reflecting spontaneous synchronization and high correlation between the condensate pseudospins as a function of pump parameters. Our findings show a new type of polarization control with exciting perspectives in both spinoptronics and studies on extended systems of interacting nonlinear optical elements with anisotropic coupling strength and adjustable fine structure.I.

Quantum vortex formation in the “rotating bucket” experiment with polariton condensates

“…With increasing optical excitation density, we observe the formation of a polariton condensate with its center of mass at the center of the excitation profile, in accordance with previous studies using an annular excitation profile (40). Because of the cylindrical asymmetry of the repulsive dumbbell-shaped exciton reservoir, here, the condensate is also spatially asymmetric as previously observed for elliptical pumping profiles (41).…”

Superfluid Polaritonic Qubit in an Annular Trap

“…2(c). The trapping also suppresses the spin-obit coupling of the polaritons [40][41][42][43][44][45][46] , and we observe a high degree of polarization of the condensate 47 A nearly perfectly circular trapping potential imposed by the pump laser supports a ring-shaped polariton condensate consisting of two coupled counter-rotating vortex modes, as described above. When, however, the pump laser profile is elliptic, we observe the double-lobe (standing-wave) structure oriented along the major axis of the ellipse, see Fig.…”

Spontaneous Formation of Time-Periodic Vortex Cluster in Nonlinear Fluids of Light

“…We note that the extracted coherence time of the condensate is t c = 426 ps which is typical for optically trapped condensates [59]. We note that the excitation beam is circularly polarized and, through additional polarizationresolved measurements (see Supplemental Material), we confirm that the condensate is also strongly circularly polarized which indicates that spin dynamics (e.g., selfsustained Larmor precession) cannot be responsible for the observed oscillations [59,60].…”