arXiv subjects

Marti Struve

Publications and source records attributed to Marti Struve.

4 recordsLinked to original sources

arXiv2026

Coherent interaction of WS$_2$ and quasi-2D perovskite excitons over micrometer distances via a cavity field

The coherent coupling of cavity-confined photons and excitonic matter resonances leads to the formation of cavity polaritons, hybrid light-matter quasi-particles. If multiple exciton resonances couple to the same photonic mode, the resulting polariton constitutes a coherent interaction between matter resonances that can be spatially separated without any direct electronic coupling. In this work, we demonstrate the formation of such a coherent coupling at room temperature using an open optical cavity containing two distinct van der Waals materials - monolayer WS2 and layered quasi-2D halide perovskites (HaPs) - separated by $1.5 \mu\rm m$. The system forms three polariton branches, with the middle branch possessing nearly equal fractions of both excitons and the photonic mode. White-light reflectivity and luminescence measurements are in good agreement with simulations using a coupled harmonic oscillator and a microscopic Wannier-Hopfield framework. Our results lay the foundation to combine highly complementary degrees of freedom in 2D materials in an in-situ tunable fashion to enable new polaritonic functionalities.

cond-mat.mes-hall↗

arXiv2025

Exciton-polariton condensate in the van der Waals magnet CrSBr

Van der Waals magnets are an emergent material class of paramount interest for fundamental studies in coupling light with matter excitations, which are uniquely linked to their underlying magnetic properties. Among these materials, the semiconducting magnet CrSBr is possibly a first playground where we can study simultaneously the interaction of photons, magnons, and excitons at the quantum level. Here we demonstrate a coherent macroscopic quantum phase, the bosonic condensation of exciton-polaritons, emerging in a CrSBr flake embedded in a fully tunable cryogenic open optical cavity. The Bose condensate is characterized by a highly non-linear threshold-like behavior, and coherence manifests distinctly via its first and second order quantum correlations. We find that the condensate's non-linearity is highly susceptible to the magnetic order in CrSBr. Specially, it can encounter a sign change from attractive to repulsive interactions when the intrinsic antiferromagnetic order transforms to the forced ferromagnetic order. Our findings open a route towards magnetically controllable quantum fluids of light, and optomagnonic devices where spin magnetism is coupled to on-chip Bose-Einstein condensates.

cond-mat.mtrl-sci↗

arXiv2024

Room-temperature polariton condensate in a two-dimensional hybrid perovskite

Layered 2D halide perovskites are chemically synthesized realizations of quantum well stacks with giant exciton oscillator strengths, tunable emission spectra and very large exciton binding energies. While these features render 2D halide perovskites a promising platform for room-temperature polaritonics, bosonic condensation and polariton lasing in 2D perovskites have so far remained elusive at ambient conditions. Here, we demonstrate room-temperature cavity exciton-polariton condensation in mechanically exfoliated crystals of the 2D Ruddlesden-Popper iodide perovskite $(BA)_{2}(MA)_{2}Pb_{3}I_{10}$ in an open optical microcavity. We observe a polariton condensation threshold of $P_{th}=6.76 fJ$ per pulse and detect a strong non-linear response. Interferometric measurements confirm the spontaneous emergence of spatial coherence across the condensate with an associated first-order autocorrelation reaching $g^{(1)}\approx 0.6$. Our results lay the foundation for a new class of room-temperature polariton lasers based on 2D halide perovskites with great potential for hetero-integration with other van-der-Waals materials and combination with photonic crystals or waveguides.

physics.optics↗

arXiv2024

Organic room-temperature polariton condensate in a higher-order topological lattice

Organic molecule exciton-polaritons in photonic lattices are a versatile platform to emulate unconventional phases of matter at ambient conditions, including protected interface modes in topological insulators. Here, we investigate bosonic condensation in the most prototypical higher-order topological lattice: a 2D-version of the Su-Schrieffer-Heeger (SSH) model, supporting both 0D and 1D topological modes. We study fluorescent protein-filled, structured microcavities defining a staggered photonic trapping potential and observe the resulting first- and higher-order topologically protected modes via spatially resolved photoluminescence spectroscopy. We account for the spatial mode patterns by tight-binding calculations and theoretically characterize the topological invariants of the lattice. Under strong optical pumping, we observe bosonic condensation into the topological modes. Via interferometric measurements, we map the spatial first-order coherence in the protected 1D modes extending over 10 microns. Our findings pave the way towards organic on-chip polaritonics using higher-order topology as a tool for the generation of robustly confined polaritonic lasing states.

physics.optics↗