苏州大学模板.pptxVIP

苏州大学模板第1页/共16页 Contents4Conclusion and Prospect1 Background2Structure and Principle3Simulation and Analysis第2页/共16页 BackgroundOptical waveYadong Xu. Scientific reports, 2015Acoustic waveYangbo Xie. Nat. com., 2014第3页/共16页 Structure and Principle第4页/共16页 Simulation and Analysis第5页/共16页 Simulation and Analysis第6页/共16页 Simulation and Analysis第7页/共16页 Simulation and Analysis第8页/共16页 Simulation and Analysis第9页/共16页 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).第10页/共16页 Thank you for your attention!第11页/共16页 relevant?parameter第12页/共16页 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. 第13页/共16页 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 , which means that only the fundamental waveguide mode can survive in the slits.第14页/共16页 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. Fo