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 behavior 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, 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.
Professor Tony Low leads the theory and computational nanoscience group in the department of Electrical & Computer Engineering at the University of Minnesota. Low obtained his doctoral degree from the National University of Singapore in 2008. Prior to joining University of Minnesota, Low worked as an in-house theorist at various experimental groups at Columbia University, Yale University and IBM Thomas J. Watson Research. While at IBM, from 2011-2014, Low served as an industry liaison to various Universities under the Nanoelectronics Research Initiative with the goal of finding the next electronics switch. Low received the several awards from IBM and was recipient of various fellowships, and published several high impact research/review papers in Nature Photonics, Nature Nanotechnology, Physical Review Letters, etc.