Tailoring Dispersion of Room-Temperature Exciton-Polaritons with Perovskite-Based Subwavelength Metasurfaces

Abstract

Exciton-polaritons, elementary excitations arising from the strong coupling regime between photons and excitons in insulators or semiconductors, represent a promising platform for studying quantum fluids of light and realizing prospective all-optical devices. Among different materials for room temperature polaritonic devices, twodimensional (2D) layered perovskites have recently emerged as one of the promising candidates thanks to their prominent excitonic features at room temperature. Here we report on the experimental demonstration of exciton-polaritons at room temperature in resonant metasurfaces made from a subwavelength 2D lattice of perovskite pillars. These metasurfaces are obtained via spincoating, followed by crystallization of the perovskite solution in a pre-patterned glass backbone. The strong coupling regime is revealed by both angular-resolved reflectivity and photoluminescence measurements, showing anticrossing between photonic modes and the exciton resonance with a Rabi splitting in the 200 meV range. Moreover, we show that the polaritonic dispersion can be engineered by tailoring the photonic Bloch mode to which perovskite excitons are coupled. Linear, parabolic, and multi-valley polaritonic dispersions are experimentally demonstrated. All of our results are perfectly reproduced by both numerical simulations based on a rigorous coupled wave analysis and an elementary model based on a quantum theory of radiation-matter interaction. Our results suggest a new approach to study exciton-polaritons and pave the way towards large-scale and low-cost integrated polaritonic devices operating at room temperature.

Engineering a light–matter strong coupling regime in perovskite-based plasmonic metasurface: quasi-bound state in the continuum and exceptional points

“…Beside the electrical properties of the metal film, we will exploit its surface plasmons coupled with excitons of the perovskite to realize the formation of exciton-surface plasmon polaritons which have also been observed in several works [6,41]. Lately, it has been demonstrated that perovskite-based metasurface of subwavelength periodic lattice offers an on-demand energy-momentum polaritonic dispersion [47]. While this work only discussed on the real part (i.e.…”

“…To model the perovskite material, we use the dielectric function of phenethylammonium lead [27,31,37,42,47]. In this model, the excitonic resonance is described by a Lorentz oscillator, with dielectric function given by [54]:…”

“…The metallic substrate is made of silver with dielectric function taken from the literature [55]. The superstrate is made of Poly-methyl methacrylate (PMMA, = 1.49) to mimic real configurations in which perovskite layers are often encapsulated in a polymer layer to avoid the impact of moisture [47,56]. Kretschmann-Raether configuration [57] .…”

“…Up to now, making use of perovskite platform, different groups have successfully demonstrated polariton Bose-Einstein condensation (i.e. polariton lasing) [32][33][34][35][36][37][38][39], laser cooling [40], ballistic propagation [33], exciton-surface plasmon polaritons [6,41], polaritonic microstructures [33,[42][43][44] and lattices [36,[45][46][47]. However, the polaritonic devices reported in these works are optically pumped.…”

Room Temperature Polariton Lasing in Ladder‐Type Oligo(p‐Phenylene)s with Different π‐Conjugation Lengths

“…[ 7 ] A broad spectrum of active layers is currently being investigated among inorganic semiconductors (such as GaN, [ 8 ] ZnO, [ 9 ] and perovskites [ 10,11 ] ), organic semiconductors, and hybrid materials. [ 12–15 ] Organic semiconductors contain localized Frenkel excitons with high exciton binding energy (of several hundreds of meV) and high oscillator strength. These attractive properties enable demonstration of strong coupling at room temperature.…”