Room temperature exciton–polariton Bose–Einstein condensation in organic single-crystal microribbon cavities

Abstract

Exciton–polariton Bose–Einstein condensation (EP BEC) is of crucial importance for the development of coherent light sources and optical logic elements, as it creates a new state of matter with coherent nature and nonlinear behaviors. The demand for room temperature EP BEC has driven the development of organic polaritons because of the large binding energies of Frenkel excitons in organic materials. However, the reliance on external high-finesse microcavities for organic EP BEC results in poor compactness and integrability of devices, which restricts their practical applications in on-chip integration. Here, we demonstrate room temperature EP BEC in organic single-crystal microribbon natural cavities. The regularly shaped microribbons serve as waveguide Fabry–Pérot microcavities, in which efficient strong coupling between Frenkel excitons and photons leads to the generation of EPs at room temperature. The large exciton–photon coupling strength due to high exciton densities facilitates the achievement of EP BEC. Taking advantages of interactions in EP condensates and dimension confinement effects, we demonstrate the realization of controllable output of coherent light from the microribbons. We hope that the results will provide a useful enlightenment for using organic single crystals to construct miniaturized polaritonic devices.

Microcavity-like exciton-polaritons can be the primary photoexcitation in bare organic semiconductors

“…topochemically grown crystals, or when there are light-management constraints. Furthermore, the absence of an external microcavity reduces the device footprint and allows for easier guiding of EPs as recently demonstrated for the Bose-Einstein condensation of polaritons in bare organic crystals 90 . The persistence of cavity-free EP formation at room temperature and in the presence of comparatively high levels of disorder, which would typically hamper many other systems e.g.…”

Exciton‐Polaritons and Their Bose–Einstein Condensates in Organic Semiconductor Microcavities

“…Apart from wavelength tunability, we had lately demonstrated a direction tunable organic polariton laser. [52] Unlike the aforementioned configurations relying on external mirrors (either DBR or Ag mirror), our result was based on natural microresonators formed by single-crystalline microribbons. Despite the limited [61] Copyright 2016, The Authors, published by American Association for the Advancement of Science.…”

“…Reproduced under the terms of the CC‐BY Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0). [ 52 ] Copyright 2021, The Authors, published by Springer Nature.…”

“…c) Schematic representation and experimental demonstration of a pump power-and temperature-controlled direction-tunable polariton laser based on repulsive interactions within polariton condensates in a PDI-O microribbon. Reproduced under the terms of the CC-BY Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0) [52]. Copyright 2021, The Authors, published by Springer Nature.…”

“…Meanwhile, in 2D planar cavities, fruitful organic electronically excited-state processes can be dramatically modified due to the formation of cavity polaritons, [6][7][8][9] allowing observation of extraordinary photochemistry and photophysics of organic molecules, such as altered chemical reactions, [10,11,[25][26][27] long-range energy transfer, [28][29][30][31][32][33][34] modulated single/triplet dynamics, [35][36][37][38][39][40][41][42][43][44][45] and enhanced nonlinear optical effects. [46][47][48][49] More importantly, room temperature polariton condensation and related phenomena such as polariton lasing, superfluidity have been demonstrated in planar cavity structures with a broad range of organic materials, [50] including single crystals [51][52][53] and thin films based on conjugated polymers, [54,55] oligomers, [56,57] molecular dyes, [58][59][60] and fluorescent proteins. [61,62] These experimental pr...…”