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Materials-Metals 2017
Page 24
November 16-17, 2017 Paris, France
13
th
Annual Conference on
Materials Science, Metal and Manufacturing
Journal of Materials Science and Nanotechnology
Volume 1 Issue 2
Jiangnan Si et al., Mater Sci Nanotechnol 2017, 1:2
Independently tunable dual-band coherent
perfect absorption based on metal-graphene
metasurface
Jiangnan Si, Xiaoxu Deng
and
Xianyi YU
Shanghai Jiao Tong University, China
A
dual-band polarization-independent device based
on metal-graphene nanostructures is proposed to
realize coherent perfect absorption(CPA) at mid-infrared
frequencies, which is composed of golden nanorings with two
different sizes placed on graphene finger set. By controlling the
relative phase of two incident countering-propagating beams,
the coherent absorption at two resonant frequencies can be
tuned from 0% to 98.3% and 0% to 98.4% separately. Besides,
the coherent absorption can be tuned by the Fermi energy
of corresponding graphene finger set, without changing the
geometrical parameter of the nanostructures. The finite-
difference time-domain (FDTD) solutions are employed to
simulate the characteristics of the hybrid metal-graphene
dual-band device. Distinguishing from the conventional
graphene CPA devices, multiple CPA resonances in the hybrid
metal-graphene CPA device are independently modulated by
changing bias voltages applied on graphene finger set, which
can be widely used in practical applications such as sensors,
filters and switchers.
Image:
The designed metamaterials for dual-band light CPA
of monolayer graphene is sandwiched between the designed
nanostructure and the SiO
2
substrate. The designed metal
nanostructure is composed of golden nanorings with two
different sizes within a unit cell. The small size of nanoring is
in the center of the unit cell and the big size of nanoring is at
the four corners of the unit cell.
Figure 1:
(a) The simulated absorption, reflection and
transmission spectra of the small size of golden nanoring
on graphene finger set when the Fermi energy EF=0.35eV
and the two coherent beams with the same intensities
and phases. (b) The simulated absorption, reflection and
transmission spectra of the big size of golden nanoring on
graphene finger set. (c) The simulated absorption spectra of
two sizes of golden nanorings on graphene finger set.
Figure 2:
(a) When the phase difference between two
countering-propagating coherent beams is 90°, the simulated
absorption, reflection and transmission spectra of two
sizes of golden nanorings on graphene finger set. (b)When
the phase difference between two countering-propagating
coherent beams is 180°, the simulated absorption, reflection
and transmission spectra of two sizes of golden nanorings on
graphene finger set.
Figure 3:
The simulated absorption of the designed metal-
graphene nanostructure with different EF=0.35eV, 0.45eV
and 0.65eV.
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