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【管理资料】苏州大学ppt模板汇编
survive in the slits.
When the flat metasurface is bent into a metacage, the rectangular shaped slit will change into sectors.
Would this change affect the results?
In fact, the material profile is accurately obtained for the matched-impedance GIMs by modulating phase profile inside slits. While for the case of mismatched-impedance GIMs, due to the scattering arising from mismatched impedance between air and silts, a tiny deviation of phase profile could emerge. As a result, for an incident wave, the destructive interferences of the transmitted waves are not perfect, so that some outgoing wave couples to the propagation order n=1, giving rise to a little transmission in the outgoing space.
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n6 2.875 a
i k
n5 2.5 n42.125
n3 1.75
TE (TM )
d /3 n2 1.375
n1
•••
1
d /3
p 1/ 2
a1/8P=1/16 w3/4a3/64
=8 m
why does there exist certain transmission for the TM incidence?
Simulation and Analysis
Simulation and Analysis
Simulation and Analysis
Simulation and Analysis
Simulation and Analysis
Conclusion and Prospect
In conclusion, we have demonstrated that metallic grating structure with gradient index materials could be used to obtain nearly total omnidirectional reflection, regardless of the polarizations of incident wave and the impedance properties of the filled materials.
This work has been published in Europhys. Lett., 114(3), 34003 (2016).
Thank you for your attention!
relevant parameter
•••
d
y
n1 1
w d /3 n8 3.625
ackground
Optical wave
Acoustic wave
Yadong Xu. Scientific reports, 2015
Yangbo Xie. Nat. com., 2014
Structure and Principle
ni 1(i1)/m d
k 0sini k 0sint n G .
It is possible that higher order of waveguide modes appear?
In our work, the width of each slit is 3/64 and
the maximal refractive index of the filling
To construct a whole metallic grating ring, the supercells are bent into a sector ring, so that the rectangular shaped slits will change into sectors. For reducing the deviation caused by bending the grating structure, a metallic grating ring with a smaller curvature are required. With combining the enablement of constructing the grating ring and the reflection effect for the grating ring, in our design, the whole metallic grating ring includes 18 sectors.
materials is 3.625. Therefore, the highest
order modes exists in our waveguide slit
is
m 2,nwm ahxw ich/ m ea0 n.3 s4 that
only the fundamental waveguide mode can