苏州大学ppt模板

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).
ni 1 (i 1) / md
k0 sin i k0 sin t nG.
Simulation and Analysis
Simulation and Analysis
Simulation and Analysis
Simulation and Analysis
Simulation and Analysis
3 4
Simulation and Analysis
Conclusion and Prospect
Background
Optical wave Acoustic wave
Yadong Xu. Scientific reports, 2015
Yangbo Xie. Nat. com., 2014
Structure and Principle
Thank you for your attention!
relevant parameter
n1 1 d /3 n8 3.625
d

y
w
d /3
x
i
n7 3.25
n6 2.875
n5 2.5
a
p 1/ 2
a 1/8P=1/16
w 3/ 4a 3/ 64
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 materials is 3.625. Therefore, the highest order modes exists in our waveguide slit is m 2nmax w / 0.34 , which means that only the fundamental waveguide mode can 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 nstruct 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.
Total omnidirectional reflection by sub-wavelength gradient metallic gratings
tutor ：Huanyang Chen student：Erting Qian
Contents
1 2
Background
Structure and Principle
k
d /3
n4 2.125
n3 1.75
TE (TM )
n2 1.375 n1 1

=8m
why does there exist certain transmission for the TM incidence?
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.