| The plasma refractive index sensor based on the narrow-band metamaterial absorber has wider application in the fields of biology,chemistry and medicine.However,at present,there are still two problems in the field of sensor applications of the narrow-band absorption metamaterials,such as the low figure of merit and the complex structure.Therefore,it is a research hotspot to explore the physical mechanism for designing a narrow-band absorber with high figure of merit and simple structure.The dissertation carries out the theoretical analysis and optimization of the model we proposed from the equivalent LC circuit,the distribution of the electromagnetic field,the structural parameters and so on.The sensing characteristics of the designed structures are greatly improved.All in all,The main research results of this dissertation are listed as follows:(1)In the visible light region,the structure has the high absorption efficiency exceeding 95%.Operated as a plasmonic refractive index sensor,this structure greatly improves the accuracy of the plasmonic sensors in visible region.Its reflectivity dip under 0.001,sensitivity is around 425nm/RIU with the full width at half maximum of the spectrumof only 1.82nm.And the figure of merit can reach 233.5.(2)In infrared region,the plasmonic refractive index sensor based on the simplest structure with pure-metal-grating is presented,it has ultra-narrow band absorption and ultra-high sensitivity.The absorber presents a perfect absorption efficiency of over 98%with an ultra-narrow bandwidth of 0.66nm at normal incidence.When operated as a plasmonic refractive index sensor,the ultra-narrow band absorber has an ultra-high wavelength sensitivity 2400nm/RIU and figure of merit 3640.Due to the simplicity of its geometry structure and its high sensitivity,the above-mentioned the plasma sensor based on the narrow-band metamaterial absorber indicates a competitive candidate for applications in sensing or detecting fields. |
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