Research On The Transmission And Regulation Of Optical Field Based On Optical Waveguide

Entering this century,the speed of science and technology development is truly breathtaking.Various devices are becoming more and more micro-nano and integrated.Compared with traditional electronic devices,photonic devices have unique and excellent characteristics.However,in the early years,the photonic devices were limited by optical diffraction,and could not be further miniaturized and could not meet the requirements of highly integrated devices.Nowadays,Surface Plasmons(SPs)can effectively solve these technical difficulties.Because it can perfectly break the limit of optical diffraction,many researchers turn their attention to it,which provides the possibility to effectively solve the above problems.This thesis is mainly based on the SP waveguide structure and analyzes its characteristics of the transmission and regulation of incident light.At the same time,we analyze the regulation characteristics of the anisotropy of incident light in the optical waveguide without plasmon response.The specific research content of the thesis is as follows:(1)The waveguide system based on graphene-edge-mode to regulate light transmission is explored.Plasmon-induced absorption(PIA)is achieved through near-field coupling.Using the finite-difference time-domain method,the physical origin of the absorption of the transmitted light is understood,which benefits from the interference cancellation between the radiation mode and the subradiation mode of the graphene nanoribbons.The tunability of graphene Fermi energy is used to dynamically adjust the resonance wavelength.At the same time,it is found that the waveguide structure has excellent sensing performance.In addition,the group delay time at the absorption window can reach-0.28 ps,which shows that it has good fast light characteristics.Finally,new graphene nanoribbons are introduced,and a dual-channel absorption window is fabricated.This work provides theoretical guidance for integrated plasmon sensor devices.(2)The waveguide system based on bulk Dirac semimetal(BDS)material to regulate light transmission is explored.With the help of numerical simulation,it is known that the waveguide structure can realize the PIA effect.The classic three-level theory can explain the reason for the formation of the absorption window,which is attributed to the strong destructive interference between the light and dark modes.It is worth noting that the dielectric constant of the BDS is controlled by Fermi energy,and the modulation ratio of the absorption window can be easily adjusted.At the same time,the coupling distance between the resonant cavity and the ring resonator can control the working frequency of the absorption window in the horizontal direction.Moreover,the waveguide system is extremely sensitive to the refractive index of the environment.In addition,the good fast light response is due to the group delay time at the absorption window which can reach-57.2 ps.Finally,the dual-channel absorption window is also analyzed,which provides a design platform for excellent optical transmission devices.(3)The waveguide system based on hybrid BDS-Photoactive Silicon to regulate light transmission is explored.Numerical simulation shows that the waveguide structure can achieve plasmon-induced transparency(PIT)effcet to transmitted light.The introduction of coupled mode theory(CMT)proves that this phenomenon is caused by the strong destructive interference between two special paths.At the same time,the formation conditions of the best transparent window can be theoretically deduced.Interestingly,the dielectric function of BDS is regulated by Fermi energy,and the position of the transparent window can be dynamically tuned;moreover,the intensity of the pump light source can change the conductivity of Photoactive Silicon,so that the height of the transparent peak can be easily adjusted.Using these two methods to control the resonance characteristics of the incident light at the transparent window will have practical application value in multifunctional integrated photonic devices.(4)The waveguide system based on hybrid In Sb-Photoactive Silicon to regulate light transmission is explored.Simulation calculations show that there is a PIT effect in the waveguide.With the aid of CMT analysis,it is concluded that this phenomenon is caused by the perfect cancellation of two different coherent paths.It is worth noting that the coupling distance between the two resonant cavities can control the resonance frequency of the transmitted light.Studies have found that adjusting the intensity of the pump light can change the conductivity of Photoactive Silicon,thereby realizing dynamic modulation of the transparent window;at the same time,temperature can control the dielectric function of In Sb,so that the characteristics of the transmission spectrum are controlled by temperature.Therefore,the modulation methods based on light control and temperature control do not need to reconstruct the waveguide,which provides theoretical guidance for more complex application scenarios.(5)The guided resonance system based on hybrid black phosphorous(BP)-silicon grating to regulate light transmission is explored.The system is constructed from a single layer of BP and silicon grating,which is then placed on a gold substrate isolated by silicon dioxide.Numerical simulations have found that the absorption efficiency of the system for transmitted light is as high as 99.9% in the direction of the armchair,but only 87.2% in the direction of the zigzag.This is due to the in-plane anisotropy of the BP itself.The CMT proves that perfect light absorption is attributed to the critical coupling mechanism with guided resonance.Interestingly,this guided resonance system has no plasmon response,but it greatly enhances the absorption efficiency of the transmitted light.At the same time,it was found that the electron doping rate of BP can dynamically control the absorption spectrum.Finally,the dependence of the structure on the relevant angle parameters of the incident light is analyzed.It is demonstrated that the simple and easy-to-manufacture structure has excellent and promising potential applications in tunable high-performance devices based on BP.