Tunable Band-Stop Filters for Graphene Plasmons Based on Periodically Modulated Graphene

Abstract

Tunable band-stop filters based on graphene with periodically modulated chemical potentials are proposed. Periodic graphene can be considered as a plasmonic crystal. Its energy band diagram is analyzed, which clearly shows a blue shift of the forbidden band with increasing chemical potential. Structural design and optimization are performed by an effective-index-based transfer matrix method, which is confirmed by numerical simulations. The center frequency of the filter can be tuned in a range from 37 to 53 THz based on the electrical tunability of graphene, while the modulation depth (−26 dB) and the bandwidth (3.1 THz) of the filter remain unchanged. Specifically, the bandwidth and modulation depth of the filters can be flexibly preset by adjusting the chemical potential ratio and the period number. The length of the filter (~750 nm) is only 1/9 of the operating wavelength in vacuum, which makes the filter a good choice for compact on-chip applications.

Wide-range tunable subwavelength band-stop filter for the far-infrared wavelengths based on single-layer graphene sheet

“…[18] reveals tuning, although its resonance wavelengths are too close to each other. One more plasmonic band-stop filter is composed of periodically modulated graphene deposited over silicon-oxide insulator and multigrating silicon substrate [19]. A wide enough tuning range reached in this study (37-53 THz) is owing to tuning of the chemical voltage applied to graphene waveguide.…”

Investigation of the Band Structure of Graphene-Based Plasmonic Photonic Crystals

“…Practically, the means of fabrication of the proposed nano-cavity can follow the method proposed in Reference [34], where the graphene monolayer sits on a SiO 2 on Si substrate. The thickness of the SiO 2 layer is periodically modified to get the chemical potential of the graphene periodical variation when external electric field is applied.…”

“…Unlike the conventional plasmonics based on noble metals, graphene supported SPPs have demonstrated extremely high confinement, highly tunability via electrical gating and chemical doping [26,27,28], and relatively low loss resulting from long plasmon lifetime [29,30]. These extraordinary properties make graphene a promising candidate for plasmonic material with broad applications from terahertz to mid-infrared span [31,32,33,34]. …”

Tunable reflecting terahertz filter based on chirped metamaterial structure

“…A few interesting and useful functionalities have been demonstrated from metamaterial-based devices, including negative refractive index components4, perfect absorbers5678, modulators91011, and filters12131415. Metamaterial concepts have also been widely applied in developing active terahertz filters by means of optical, electronic, and thermal stimulation151617181920212223. And optical tuning of metamaterials is very attractive due to its fast speed16242526.…”

“…Bandstop filter is commonly used to selectively eliminate undesired information and suppress interfering signals. So far, many tunable bandstop filters based on metamaterials1720212223, such as mechanically tunable bandstop filters17202122, dynamic modulator based on microfluidic metasurface23, and active plasmonic bandstop filters resulting from varying of the chemical potential of graphene1530, have been proposed.…”