Research On Sensing Characteristics Based On Multi-Fano Resonance Waveguide Structure

Surface plasmon polaritons(SPPs)have gradually developed into a new discipline today and have received extensive research and attention.Surface plasmon is a manifestation of electromagnetic surface waves,which is specifically expressed as the collective oscillation of free electrons.Its special physical properties make it possible to integrate and miniaturize micro-nano-level metal optical components.Research has found that surface plasmons can produce resonant coupling effects under certain conditions,and can produce special sharp asymmetric transmission spectral lines.This phenomenon is called Fano resonance effect.The special properties of Fano resonance are widely used in the field of micro-nano optical devices.Among them,the sensor is one of the most promising applications of surface plasmons.It has good advantages,including but not limited to high sensitivity,small size and easy integration.And so on,it has a positive meaning for the realization of high integration and high availability of the new micro-nano photonic circuit.Based on the above content,the main research contents of this article are as follows:1.This article first introduces the simple concepts of surface plasmon and Fano resonance effect.Since the research content of this article is in the field of refractive index sensors,mathematical explanations are made on the characterization methods of the sensing characteristics of refractive index sensors,and finally The research status of sensors based on multi-Fano resonant waveguide structure is described.2.Introduced the basic principles of surface plasmons,and introduced the theoretical explanation of surface plasmons starting from the basic wave equation and Maxwell equations.The coupled mode theory and scattering matrix theory that can support the theoretical explanation of the full text are introduced.Finally,the finite element method and simulation software used in this article are briefly introduced.3.Combining the latest research results in this field at home and abroad,based on the above basic research methods and basic theories,three sensing structures that can produce multi-Fano resonance effects are proposed,and the structure of the proposed structure is continuously optimized to improve the sensing characteristics.The first is a waveguide structure in which a baffled MIM straight waveguide is coupled to a right-angled triangular cavity connected to a circular ring cavity.This structure can generate a triple Fano resonance effect;the second structure further improves the basic structure of the first structure.It is a waveguide structure with a right-angled triangular cavity connected to a plurality of tooth cavities coupled to a MIM straight waveguide with a baffle.This structure can also produce a triple Fano resonance effect;the third is a MIM straight waveguide with a baffle coupled The waveguide structure of the semicircular cavity connected to the tooth cavity can generate six times the Fano resonance effect.The innovations of this article are mainly in three aspects.Firstly,the three structures have flexible scalability.Each structure is based on a simple and reliable physical structure.By adding tooth cavities,the multiple Fano resonances studied in this article can be achieved.purpose.Secondly,the above three structures all have multi-parameter independent tunable characteristics,and the spectral line is linearly redshifted by adjusting the parameters,and the structure proposed in Chapter 5 has six-fold Fano resonance.In the current research,the peak value is digitized.Column upstream.Finally,the above three structures can be applied to the field of micro-nano refractive index sensors,with qualified sensitivity and FOM value.In summary,the three new plasmon micro-nano structures designed and proposed in this paper can generate multiple Fano resonance effects and have good sensing characteristics.They can all be applied to micro-nano refractive index sensors and advance the micro-nano structure.The research of nanophotonic devices has had a positive significance for the realization of a new type of micro-nano photonic circuit with high integration and high availability.