Design And Research Of Metasurface Absorber For Integrated Electromagnetic Wave Detector

Traditional electromagnetic wave detectors are composed of discrete components.The introduction of filters,collimating lenses,and polarizers increases the optical path length of the system and also makes the detector bulky,which is not conducive to integration and miniaturization.As a sub-wavelength-scale two-dimensional resonance unit array,the metasurface has the characteristics of planarization,compatibility with CMOS technology,and the ability to control the amplitude,phase,and polarization state of electromagnetic waves by design.By rationally designing the material and structure of the metasurface,the function of filtering,absorption,and detection can be achieved on the same chip,thereby replacing discrete components and greatly improving the integration of the detector.The research in this paper focuses on the design of specific functional metasurface absorbers for electromagnetic wave detectors.The main research work is stated as follows:(1)Design of meanderline subwavelength absorber for terahertz detection.We propose a sandwich structure of meander line gold antenna-dielectric layer-gold back plate.The size of the absorber unit is greatly reduced by the meander line design,and the absorption characteristics and regularity of the absorber are validated using the equivalent circuit model.The design results show that the absorber has an absorption rate of 89% in the target band of155?m(1.94THz),with the full width at half maximum of the absorption spectrum of 46?m,and has good polarization stability and insensitivity to the incident angle(-40° to 40°).The absorber unit is only 10?m.In addition,we studied the possible crosstalk problem of integrating the absorber into the detection pixels,and verified the feasibility of the design.On this basis,we extended our work to the infrared band and realized a wideband absorber design for infrared detection and imaging.This work provides the possibility of miniaturizing the design of detector pixels.(2)Design of narrowband angle-stable absorber for high-resolution spectral detection.We propose a sandwich structure of hexagonal lattice silicon pillar array-dielectric-gold back plate to reduce ohmic losses introduced by the plasmonic absorber,thus greatly narrowing the absorption spectrum bandwidth.And we rationally design the reflection and transmission phases of the array layer based on cavity resonance theory to ensure the angular stability of the absorber with respect to incident light.The design results show that the absorber has an absorption rate of 98% at the target band of 4.26?m.The absorption spectrum bandwidth is only 8.5nm,which means the quality factor is up to 500.And the absorber has good polarization stability and incident angular stability(-15° to 15°).We provide a multi-gas sensing application scheme by integrating absorbers with different target detection wavelengths.The absorber design can realize narrowband absorption detection at different target wavelengths by only changing the structural parameters,which provides an idea for multi-wavelength high-resolution spectral detection.