| Monolayer graphene possesses extremely superior physical and electro-optical properties due to its special band gap structure.These excellent properties make it an important application in flexible RF devices,electronic components,supercapacitors,optical sensors,conductive inks,coatings and composite materials.The Goos-H?nchen Shift(GH Shift)is referred to as GH shift,which means that when the beam is completely reflected at the interface,the reflected beam will be transversally shifted from the position predicted by geometric optics.GH shifts have distinguished themselves in the design of demultiplexers,optical switches,chemical and biological sensors,and surface roughness detectors.Generally,the magnitude of GH shift is small,so it can not be better developed in related applications.The discovery of monolayer graphene provides an unprecedented opportunity to explore GH shift.In this paper,based on the transfer matrix method,rigorous coupled wave analysis method and static phase method,the composite structure based on monolayer graphene is investigated to study the influence of GH shift of reflected waves,in order to obtain giant and tunable GH shift,the specific work are listed as follows:Firstly,GH shift of reflected waves is studied by constructing monolayers of graphene ribbons and multilayer dielectric gratings.The GH shift obtained here is up to 7300 times of the operating wave in the near infrared frequency region.We further clarify that the enhanced GH shift is due to the guided mode resonance of the top layer dielectric grating structure,and we control the GH shift size and sign by adjusting the chemical potential of the monolayer graphene ribbon.In addition,the GH shift is controlled by changing the structural parameters of the composite structure.Therefore,the composite structure opens a new way to enhance and control GH shift of reflected waves in monolayer graphene ribbon composite structures,which may contribute to their potential applications in high-resolution sensors and imaging detection.Secondly,we construct and study a structure consisting of monolayer graphene and onedimensional topological photonic crystal to study GH shift of reflected wave.The results show that the GH shift of the structure can reach 5200 times of the operating wavelength at the near infrared frequency.By analyzing the electric field diagram of the structure,it can be found that the incident electromagnetic wave energy is mainly concentrated on the interface of the one-dimensional topological photonic crystal,where the monolayer graphene is located.Therefore,it is precisely because of the existence of topological side modes at the interfaces of the two one-dimensional photonic crystals that the light field at the interfaces of the two photonic crystals is localized and the GH shift is enhanced.Furthermore,we can obtain the tunability of GH shift in the structure by changing the parameters of monolayer graphene and the geometrical parameters of the structure.The composite structure can provide reference for the application of photonic topological states in integrated photonic devices and information processing chips.Finally,we design a structure consisting of multiple monolayers of graphene and two onedimensional photonic crystals.The GH shift of reflected wave in the structure can appear three corresponding peaks from 1950 nm to 2250 nm,and the three peaks are 1270?,410? and960?,respectively.We find that the enhancement of GH shift of the structure can be attributed to the interaction between multiple monolayer graphene and one-dimensional photonic crystals promoted by light,and the three GH peaks are different due to the difference in the distribution of electric field intensity at monolayer graphene.Furthermore,the GH shift of the reflected wave in the composite structure can be precisely controlled by changing the Fermi energy and the geometrical parameters of the structure.The results of multiple GH peaks in the composite structure based on multiple monolayer graphene could pave the way for light detection,shielding and optical sensing. |
