Topological Control of 2D Perovskite Emission in the Strong Coupling Regime

Abstract

Momentum space topology can be exploited to manipulate radiation in real space. Here we demonstrate topological control of 2D perovskite emission in the strong coupling regime via polaritonic bound states in the continuum (BICs). Topological polarization singularities (polarization vortices and circularly polarized eigenstates) are observed at room temperature by measuring the Stokes parameters of photoluminescence in momentum space. Particularly, in symmetry-broken structures, a very large degree of circular polarization (DCP) of ∼0.835 is achieved in the perovskite emission, which is the largest in perovskite materials to our knowledge. In the strong coupling regime, lower polariton modes shift to the low-loss spectral region, resulting in strong emission enhancement and large DCP. Our reciprocity analysis reveals that DCP is limited by material absorption at the emission wavelength. Polaritonic BICs based on 2D perovskite materials combine unique topological features with exceptional material properties and may become a promising platform for active nanophotonic devices.

Multifunctional and Transformative Metaphotonics with Emerging Materials

“…The employment of BIC concept allows to extend the polarization control. Thus, topological polarization singularities in polariton emission was demonstrated . In this structure, a very large degree of circular polarization was achieved.…”

“…Thus, topological polarization singularities in polariton emission was demonstrated. 271 In this structure, a very large degree of circular polarization was achieved. In addition, by nanograting of perovskite nanowire, a topological defect into the nanowire can be introduced and a defectlocalized lasing state is observed.…”

Microcavity exciton polaritons at room temperature

“…By changing the lattice parameters, such as pillar height and aspect ratio, different kinds of polaritonic dispersions can be achieved with linear, parabolic, and even multivalley characteristics. After that, Kim et al further made use of similar 2D photonic crystals and realized exciton polaritons resulting from the strong coupling between optical bound states in the continuum and C 6 H 5 C 2 H 4 NH 3 2 PbI 4 perovskite excitons [308] . Interestingly, [35] .…”

Ultrahigh-Q Lead Halide Perovskite Microlasers

“…By fine-tuning symmetry or structural parameters, radiation along different decay channels of one or more resonances destructively interferes with each other and is completely inhibited . The concept of BIC has been widely employed in various nanophotonic systems and strongly boosted their device performances, , e.g., BIC lasers, ,− sensors, nonlinear optics, , topological photonics, all optical switching and optical imaging, etc. One intriguing characteristic of optical BIC is that the light trapping can be realized by engineering either the boundary of high-index materials − or its surrounding environment. − The latter is particularly important for extremely fragile or hard materials that are incompatible with conventional patterning and etching processes.…”

“…The concept of BIC has been widely employed in various nanophotonic systems and strongly boosted their device performances, , e.g., BIC lasers, ,− sensors, nonlinear optics, , topological photonics, all optical switching and optical imaging, etc. One intriguing characteristic of optical BIC is that the light trapping can be realized by engineering either the boundary of high-index materials − or its surrounding environment. − The latter is particularly important for extremely fragile or hard materials that are incompatible with conventional patterning and etching processes. Herein, we combine the concept of etchless optical BIC and single-crystalline CsPbBr 3 perovskite to demonstrate on-chip integrated coherent light sources with record high Q factors.…”