title: Polaritons in layered two-dimensional materials.
abstract: In recent years, enhanced light-matter interactions through a plethora of dipole-type polaritonic excitations have been observed in two-dimensional (2D) layered materials. In graphene, electrically tunable and highly confined plasmon-polaritons were predicted and observed, opening up opportunities for optoelectronics, bio-sensing and other mid-infrared applications. In hexagonal boron nitride, low-loss infrared-active phonon-polaritons exhibit hyperbolic behaviour for some frequencies, allowing for ray-like propagation exhibiting high quality factors and hyperlensing effects. In transition metal dichalcogenides, reduced screening in the 2D limit leads to optically prominent excitons with large binding energy, with these polaritonic modes having been recently observed with scanning near-field optical microscopy. Here, we review recent progress in state-of-the-art experiments, and survey the vast library of polaritonic modes in 2D materials, their optical spectral properties, figures of merit and application space. Taken together, the emerging field of 2D material polaritonics and their hybrids provide enticing avenues for manipulating light-matter interactions across the visible, infrared to terahertz spectral ranges, with new optical control beyond what can be achieved using traditional bulk materials.
authors.affiliation: Department of Electrical &Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Tony
authors.initials: T
authors.lastname: Low
authors.affiliation: Universidade Federal do Ceará, Departamento de Física, Caixa Postal 6030, 60455-760 Fortaleza, Ceará, Brazil.|Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: Andrey
authors.initials: A
authors.lastname: Chaves
authors.affiliation: US Naval Research Laboratory, 4555 Overlook Avenue SW, Washington DC 20375, USA.
authors.forename: Joshua D
authors.identifier: 0000-0003-0374-2168
authors.initials: JD
authors.lastname: Caldwell
authors.affiliation: Department of Electrical &Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.|Mechanical Engineering Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Anshuman
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Mechanical Engineering Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Nicholas X
authors.initials: NX
authors.lastname: Fang
authors.affiliation: IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA.
authors.forename: Phaedon
authors.initials: P
authors.lastname: Avouris
authors.affiliation: Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Tony F
authors.initials: TF
authors.lastname: Heinz
authors.affiliation: IMDEA Nanociencia, Calle de Faraday 9, E-28049 Madrid, Spain.|Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Francisco
authors.initials: F
authors.lastname: Guinea
authors.affiliation: Instituto de Ciencia de Materiales de Aragon and Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, E-50012 Zaragoza, Spain.
authors.forename: Luis
authors.identifier: 0000-0001-9273-8165
authors.initials: L
authors.lastname: Martin-Moreno
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.|ICREA Institució Catalana de Recerça i Estudis Avancats, 08010 Barcelona, Spain.
authors.forename: Frank
authors.initials: F
authors.lastname: Koppens