Graphene Nano-Optics in the Terahertz Gap

Research output: Contribution to journalResearch articleContributedpeer-review



Graphene nano-optics at terahertz (THz) frequencies (ν) is theoretically anticipated to feature extraordinary effects. However, interrogating such phenomena is nontrivial, since the atomically thin graphene dimensionally mismatches the THz radiation wavelength reaching hundreds of micrometers. Greater challenges happen in the THz gap (0.1-10 THz) wherein light sources are scarce. To surpass these barriers, we use a nanoscope illuminated by a highly brilliant and tunable free-electron laser to image the graphene nano-optical response from 1.5 to 6.0 THz. For ν < 2 THz, we observe a metal-like behavior of graphene, which screens optical fields akin to noble metals, since this excitation range approaches its charge relaxation frequency. At 3.8 THz, plasmonic resonances cause a field-enhancement effect (FEE) that improves the graphene imaging power. Moreover, we show that the metallic behavior and the FEE are tunable upon electrical doping, thus providing further control of these graphene nano-optical properties in the THz gap.


Original languageEnglish
Pages (from-to)3913-3920
Number of pages8
JournalNano letters
Issue number9
Publication statusPublished - 10 May 2023

External IDs

Scopus 85159578475
WOS 000984429000001
Mendeley 72b2c8f1-eb13-3335-8434-db75fc5706d7



  • Free-electron laser, Graphene, Near-field, Plasmon-polaritons, Terahertz, plasmon-polaritons, terahertz, free-electron laser, near-field, graphene