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Title: Plasmonics in graphene at infrared frequencies

Journal Article · · Phys. Rev. B
 [1];  [1];  [2]
  1. Univ. of Zagreb (Croatia)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

We point out that plasmons in doped graphene simultaneously enable low losses and significant wave localization for frequencies below that of the optical phonon branch ℏωOph ≈0.2 eV . Large plasmon losses occur in the interband regime (via excitation of electron-hole pairs), which can be pushed toward higher frequencies for higher-doping values. For sufficiently large dopings, there is a bandwidth of frequencies from ωOph up to the interband threshold, where a plasmon decay channel via emission of an optical phonon together with an electron-hole pair is nonegligible. The calculation of losses is performed within the framework of a random-phase approximation and number conserving relaxation-time approximation. The measured DC relaxation-time serves as an input parameter characterizing collisions with impurities, whereas the contribution from optical phonons is estimated from the influence of the electron-phonon coupling on the optical conductivity. Optical properties of plasmons in graphene are in many relevant aspects similar to optical properties of surface plasmons propagating on dielectric-metal interface, which have been drawing a lot of interest lately because of their importance for nanophotonics. Therefore, the fact that plasmons in graphene could have low losses for certain frequencies makes them potentially interesting for nanophotonic applications.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
DOE Contract Number:
SC0001299; FG02-09ER46577
OSTI ID:
1064711
Journal Information:
Phys. Rev. B, Vol. 80; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English