Design And Response Characteristics Of Metasurface Sensor Based On Coupling Resonance Of Light Wave

Metasurfaces are arranged in two dimensions according to certain laws to achieve specific electromagnetic properties.According to the material,the metasurface can be divided into two types: full dielectric metasurface and metallic metasurface.One of the most popular applications is the all-dielectric metasurface due to its low ohmic loss,simple process and wide range of applications in several frequency bands such as nearinfrared and terahertz.Fano resonance and electromagnetically induced transparency are two typical phenomena in which optical waves are coupled to specific resonant structures in the medium,and strong enhancement of the local field is achieved by suppressing the radiation loss of the system.The optical wave resonance phenomenon of coupling has important applications in sensing,switching,and communication fields.Nowadays,there is a wide range of metasurface resonant sensor devices,but there are problems such as complex device structure,high processing defect rate,difficult to achieve active regulation,and single parameter measurement.To solve the above problems,this paper designs several all-dielectric metasurface sensors based on the relevant coupled resonance principles,as follows:First,the mechanism of the generation of Fano resonance and electromagnetic induced transparency effect is studied and analyzed.Based on Finite-Difference TimeDomain Method(FDTD)and multipole decomposition theory,the electromagnetic characteristics of the fully dielectric elliptical structure and square structure under optical waves and the dominant role of each pole in resonance are analyzed.Second,an all-dielectric metasurface dual-parametric sensing structure in the nearinfrared band is designed,which makes use of the change in the number of metasurface nanopillar rows to achieve a tunable transition from single-to double-Fano resonance.After coating the structure with a methane gas-sensitive film,the sensitivity of the two resonance peaks can be obtained as-1.47nm/ % and-1.56nm/ %,respectively,and when the refractive index is changed,the sensitivity of the two resonance peaks as400.45 nm/ RIU and 380.7 nm/ RIU,respectively.Since the two resonance peaks are generated by different mechanisms,they can be used for highly sensitive dual parametric measurements.In addition,the metasurface structure sensor has the advantages of simple and easy manufacturing,low cost,etc.,which provides some new ideas for all-dielectric dual-parameter sensing.Third,an all-dielectric metasurface dual-parameter sensor in the terahertz band is designed,which uses the electromagnetic transparency effect generated by the electric dipole and electric quadrupole resonance coupling to realize the active modulation of the resonance peak.The first resonance peak is linear in the temperature interval of280K-310 K with a sensitivity of 0.61154 GHz/K,and the second resonance peak is linear in the temperature interval of 280K-320 K with a sensitivity of 2.71 GHz/K.When the refractive index is changed,the sensitivity of the two resonance peaks are-0.0628THz/ RIU and-0.1573THz/ RIU,respectively.The sensor can be used for dual parametric detection of the refractive index and temperature variations in space.In addition,by simulating the process tolerance,the square gap ring super-surface sensor with 4um process error tolerance is obtained,which has a promising application in the field of terahertz sensing.