%0 Journal Article %T Superradiance of optical phonons in two-dimensional materials %+ Laboratoire Charles Coulomb (L2C) %+ Laboratoire de Thermique et d’Energie de Nantes (LTeN) %A Cassabois, Guillaume %A Fugallo, G %A Gil, Bernard %< avec comité de lecture %Z TTMI L2C:22-112 %@ 1554-9178 %J Physical Review Special Topics: Physics Education Research %I American Physical Society %V 4 %P L032040 %8 2022-09-12 %D 2022 %R 10.1103/PhysRevResearch.4.L032040 %Z Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Journal articles %X We study the superradiance of optical phonons during the two- to three-dimensional (2D-3D) crossover of the light-matter interaction in multilayers of atomic crystals. We show the emergence of a superradiant regime with a mode having a linewidth first increasing linearly with the number N of monolayers, and then decreasing as N^{−3} to zero because of the formation of stationary phonon polaritons. The linewidth culminates to values of the order of the longitudinal-transverse splitting. We estimate the extremum of the radiative efficiency for various 2D materials in the superradiant regime. We predict radiative efficiencies larger than 50% for optical phonons emitting between 6 and 165 μm. Superradiance appears as a key resource for mid- and far-infrared optophononics and advanced thermal management using multilayers of 2D materials as the active medium. %G English %2 https://hal.science/hal-03794436/document %2 https://hal.science/hal-03794436/file/PhysRevResearch.4.L032040.pdf %L hal-03794436 %U https://hal.science/hal-03794436 %~ CNRS %~ L2C %~ UNIV-MONTPELLIER %~ LTEN %~ NANTES-UNIVERSITE %~ NANTES-UNIV %~ UM-2015-2021 %~ UM-EPE %~ TEST3-HALCNRS