Chiral polariton transport enabled by optical spin Hall effect in perovskite waveguides

TL;DR

The paper addresses spin-controlled photonics at room temperature in nonlinear polariton systems. It demonstrates CsPbBr3 microwire waveguides supporting strong light-matter coupling without DBRs, enabling edge-lasing and OSHE-induced spin textures through TE–TM splitting. The authors observe real-space flower-petal polarization patterns and reciprocal-space Stokes textures, achieving highly chiral edge condensation with $|S_3| ≈ 0.85$ and spin-polarized propagation over tens of micrometers, including chiral transport under asymmetric pumping. The results show a scalable, ambient-platform for on-chip spin-coded information transport and nonlinear spin optoelectronics, with potential for spin filters and splitters in photonic circuits.

Abstract

Controlling the spin degree of freedom of light at the microscale is crucial for advancing photonic information processing. Spin polarized light propagation, combined with strong optical nonlinearities, unlocks new functionalities in compact photonic circuits and active spin optronic devices. Lead halide perovskite exciton polaritons uniquely combine room temperature operation, pronounced nonlinearities, and versatile microstructuring, making them a powerful platform for spin based photonic technologies. Here, we demonstrate polarized edge emission from polariton condensates in perovskite single crystals predesigned into a microwire, forming natural, DBR free cavity. Above threshold, we observe a distinct waveguiding optical spin Hall effect pattern in both real- and reciprocal-space emission, accompanied by pseudospin phase locking arising from coherence between opposite edges. Beyond static polarization textures, we achieve spin-resolved polariton edge lasing with chirality exceeding 80\% and spin-polarized signal propagation over tens of micrometres. These results establish CsPbBr3 waveguides as a promising easy to fabricate platform for on chip spin coded information transport and nonlinear spin optoelectronics.

Figures (6)

• Figure 1: OSHE in perovskite microwires with TE-TM splitting of waveguide modes.a, Dispersion relation of perovskite microwire with marked H and V polarisations. b, Real space images of polariton condensate for two linear polarizations. c, Schematic of the OSHE in perovskite microwire.
• Figure 2: Polarized condensation in perovskite microwires.a, Optical image of a representative CsPbBr3 crystals with annotated axes. b, Guided modes of the perovskite slab calculated for the case without exciton, c, Polariton dispersion calculated for the TE and TM modes inside perovskite. corresponding Hopfields coefficients. d real-space PL spectra below the condensation threshold for the two linear polarizations. e Energy-resolved excitonic (top) and polaritonic (middle) emission at 0.2 $P_\text{th}$ and edge emission 1.2 $P_\text{th}$ (bottom).
• Figure 3: Optical spin Hall effect in perovskite microwires.a Experimental and b theoretical real-space distributions of the three Stokes parameters evidencing spin-dependent transport of polaritons and resultant anisotropic flower petal polarization emission pattern. The crystals' edges are indicated by dashed lines.
• Figure 4: Pseudospin phase-locking.a, Angle-resolved spectra of the six main polarization components for the two polariton modes in a perovskite microwire. b, Stokes parameter $S_1$ for the two modes, with energies indicated in the corresponding insets. c, Stokes parameter $S_3$ for the same modes. The vertical black dashed lines at normal incidence are for better visibility.
• Figure 5: Reciprocal-space polarization patterns of coherent polariton edge emission. Experimental distributions of the three Stokes parameters $S_{1,2,3}$ for a polariton microwire pumped above condensation threshold. The wire width is $t \approx 5$$\mu m$. The appearance of fringes in the polarization profile implies coherent (phase-locked) emission from the wire edges which superimposes into a beating polarization pattern determined by the OSHE and wire width. b Corresponding calculated Stokes far field pattern by filtering Eq. \ref{['eq.cond']} around the wire edges and taking the Fourier transform.