Electrically Tunable Damping of Plasmonic Resonances with Graphene

Abstract

Dynamic switching of a plasmonic resonance may find numerous applications in subwavelength optoelectronics, spectroscopy, and sensing. Graphene shows a highly tunable carrier concentration under electrostatic gating, and this could provide an effective route to achieving electrical control of the plasmonic resonance. In this Letter, we demonstrate electrical control of a plasmonic resonance at infrared frequencies using large-area graphene. Plasmonic structures fabricated on graphene enhance the interaction of the incident optical field with the graphene sheet, and the impact of graphene is much stronger at mid-infrared wavelengths. Full-wave simulations, where graphene is modeled as a 1 nm thick effective medium, show excellent agreement with experimental results.

Electrical Modulation of Fano Resonance in Plasmonic Nanostructures Using Graphene

“…We note that the peak to the left of Fano dip shows less modulation than the peak to the right of Fano dip. This is consistent with our previous results 32 showing the impact of graphene to be stronger at longer wavelengths. Further, the measured data show a saturation effect, wherein the spectra do not significantly change at large carrier concentrations.…”

“…30,31 We recently demonstrated electrically controlled damping of the plasmon resonance in metal bowtie antennas placed on top of a graphene layer at the mid-IR wavelengths. 32 Subsequently, there were a number of devices that demonstrate the tuning of plasmonic antennas 33−36 and photonic crystal cavities 37,38 using graphene. However, strong electrical tunability of plasmonic resonances using graphene has so far been experimentally demonstrated only at the mid-IR wavelegnths.…”

“…This can be experimentally realized when carrier densities around 1 × 10 13 cm −2 are reached. 32 Such high carrier densities are very difficult to achieve through the conventional back-gate doping using a 300 nm oxide. 50 Instead we used electrochemical gating with DEME-TFSI (Diethy l m e t h y l ( 2 -m e t h o x y e t h y l ) a m m o n i u m b i s -(trifluoromethylsulfonyl) imide) as a top electrolyte to achieve the required large doping of graphene.…”

Spectrally selective chiral silicon metasurfaces based on infrared Fano resonances

“…The optical response of metal-based antennas 64,65 and metasurfaces 57 has been modified by combining them with SLG, and the extracted information was further used to estimate the carrier density in SLG 57 . However, as the spectral linewidth of metal-based structures is fairly broad, only modest changes of the optical response (transmission or reflection) of metasurfaces have been accomplished so far.…”

Photocurrent in graphene harnessed by tunable intrinsic plasmons

“…However, the limited absorption in a single layer of graphene through inter-band transitions presents a key challenge 13 . Efforts to increase absorption include building microcavities around graphene 14,15 or enhancing the interaction with light through fabrication of quantum dots 16 , bowtie antennas 17 and other plasmonic nanostructures on top of the graphene [18][19][20] . Utilizing the Drude response of free electrons in combination with heavy chemical doping, an increased absorption reaching 40% in a single graphene layer has been achieved in the far-infrared 21 .…”