Surface Plasmon Enhancement And Control Of Goos-H?nchen Shift Based On Two-dimensional Materials

The Goos-H?nchen shift refers to the phenomenon that the actual reflected light has a lateral offset with respect to the geometrically reflected light.When total reflection occurs,the incident light propagates a little distance in the medium,which is closely related to the evanescent wave in the medium.An evanescent wave refers to an electromagnetic wave that rapidly decays along the vertical direction of the interface on the side of the light-diffusing medium when the light incident from the optically dense medium to the light-diffusing medium.Usually,the longer the evanescent wave spread,the larger the GH shift.In recent years,with the rapid development of science and technology,the phenomenon of GH shift has gradually attracted people's attention,and has extensive research and application in various fields such as optics,medicine,biology and chemistry.The shift typically at the two monolayer interfaces are usually small and only comparable to the size of nanometer,which limits the application and development of GH shift.Therefore,scientists have tried various methods to enhance the GH shift.Such as the introduction of new materials or new structures to improve GH shift.The most striking of these methods is the experiments in 2004 of Yin et al.,who found that the method of exciting surface plasmon resonance can effectively increase the GH shift,the maximum lateral shift reaches almost 50 times of the incident wavelength,also,the giant shift can be positive or negative by adjusting the thickness of metal.In this way,the magnitude of the GH shift can be increased to the micron level,but obtaining a larger GH shift remains to be broken.After entering the 21st century,material science has been greatly developed,and a variety of new materials are endlessly emerging.New two-dimensional materials such as graphene,molybdenum disulfide,and black phosphorus have received considerable attention.Compared with traditional materials,they have many unique and fascinating performance that attract researches.For example,They have high strength,large surface area ratio,and very good adsorption.With the introduction of these two-dimensional materials,some traditional structures that increase GH shift are expected to be further improved and developed.In this paper,we proposed several modified structures based on the method of enhancing surface plasmon resonance to obtain larger and tunable GH shift.The innovations are as follows:(1)A new model based on long-range surface plasmon resonance coupled planar waveguide is proposed to increase the GH shift.The maximum GH shift that can be obtained for the proposed structure is 4156?.After the introduction of graphene,the lateral shift can reach as high as 6152?.Compared to conventional surface plasmon resonance structures,the shift is increased by more than two orders.In terms of applications,our structure is used as a high sensitivity sensor with a highest sensitivity of 4.68×10~7?/RIU.The research results were published on Chinese Physics B.(2)An Otto structure based on the surface plasmon resonance of graphene is proposed to increase the GH shift.The largest GH shift that can reach almost 900?.After the introduction of the nonlinear thin layer,the GH shift exhibits a bistable phenomenon,and the dynamic adjustment of the GH shift can be achieved by changing the external parameters.The research results were published on Chinese Physics B.(3)Based on the traditional surface plasmon structure,a graphene-molybdenum disulfide heterostructure is introduced to enhance the surface plasmon resonance and improve the GH shift.Theoretically researches shown that the maximum shift can be obtained as large as235.8?.When our structure is used as a high sensitivity sensor,its maximum sensitivity is5.545×10~5?/RIU.The research results were published on Optical Materials Express.These three schemes use different structures and introduce two-dimensional materials to enhance the surface plasmon resonance to increase the GH shift.In our designs,not only a very impressive GH shift but also a GH shift of the bistable effect is found,and a high sensitivity sensor based GH shift have been realized.These findings not only provide a lot of theoretical basis for the in-depth study of optics in the future,but also provide research value of GH shift.In the future,we will continue to deepen this field,achieve larger GH shift and try to make breakthroughs in applications.