Research On F-P Cavity Coupling At Micro-nano Scale

Surface plasmon polaritons(SPPs)are collective oscillations of free electrons at the metal interface,and electromagnetic waves are transmitted along the metaldielectric interface.SPPs break through the diffraction limit and can manipulate electromagnetic waves at the subwavelength scale,and have important applications in high-density integrated circuits,sensing,and chemical reaction control.Fabry-Pérot(FP,Fabry-Pérot),as a basic element in the field of optics,has important applications in the fields of filters,logic gates,nano-sensors,all-optical switches,and slow-light devices.In this essay,the finite difference time domain(FDTD)method is used to study the coupled resonance characteristics of SPPs in multiple-cavity.In this essay,metal-insulator-metal(MIM)bus waveguide coupled cavities(CCs)are designed using FDTD,and the coupled resonance characteristics of CCs are studied.In the two CCs with a baffle thickness of 15 nm,two resonance modes appear.The thickness of the middle baffle of CCs was reduced from 50 nm to 3 nm,and the resonant mode was obviously split.Through coupled mode theory(CMT)analysis,the opposite coupling and positive coupling between the two CCs introduce a phase difference,which leads to the splitting of the two resonant modes.The conditions for the resonance of the two split modes are deduced.By changing the thickness of the baffle,the wavelength of the resonant mode of the reverse coupling hardly shifts,while the wavelength of the resonance mode of the forward coupling shifts.The study shows that changing the thickness of the intermediate baffle can tune the wavelengths of the two resonant modes in a wide range,and the maximum tuning width is about 644 nm.The CCs proposed in this essay are quite different from a single-cavity optical path tuning,and the tuning of the resonant mode wavelength can be achieved by changing the thickness of the baffle.Based on the resonance characteristics of CCs,three-cavity and four-cavity structures are designed,and the resonant mode splitting occurs when the thickness of the middle baffle plate of CCs is changed.The electric field and phase of the resonant mode are analyzed,and the coupling mechanism of the resonant mode is given.This essay designs more compact components to manipulate the propagation of SPPs.The results show that different channels output different SPPs signals.A flexible multiwavelength SPPs routing element is proposed.Coupling in CCs can be applied to the design of simply integrated laser cavities,wave decomposition multiplexing devices,multiple-wavelength management devices in SPPs integrated circuits,nanosensors and other optical devices.