Research On All-dielectric-based Artificial Microstructured Photonic Devices

The study of metamaterials is an important research direction in nanophotonics,metamaterials have extraordinary physical properties that conventional substances do not possess in nature.Metamaterials can break through the diffraction limit and the response band is adjustable.Metamaterials have great application prospects in the fields of biomedicine,imaging,and photovoltaics.The research of metamaterials has included pure dielectric materials nowadays.Pure dielectrics have the advantages of low loss and high stability,which has become a research hotspot of metamaterials.The following is the main work of this paper:1.A single-channel perfect absorption structure based on pure dielectric-SiO₂is designed.The results of numerical analysis and calculation show that this absorber achieves a light absorption of more than 98%of electromagnetic waves at a wavelength of 2.14?m,and the corresponding FWHM is 20 nm.This structure also has the performance of being insensitive to polarized light.Increase the height and radius of the SiO₂disk in the narrowband absorber,and the corresponding working band will be red-shifted in the short-wave infrared.Based on the single-channel absorber,a dual-channel absorber was designed,with an absorption rate of 92%at 2.63?m and an absorption rate of 87%at 2.22?m.The corresponding FWHMs are 22 nm and 5 nm,respectively.2.Using the frequency-selective characteristics of metamaterials and the adsorption of porous silicon to water,a humidity sensor based on SiO₂-medium-metal was designed.The results show that when the increase in humidity causes the dielectric constant of porous silicon to increase,a reflection curve with a large red shift can be obtained,and the absorption rate of the resonance wavelength and the working position will change significantly,which is suitable for humidity detection.3.A broadband perfect absorber structure based on SiO₂is proposed.Using the principle of multi-layer film to broaden the band of the SiO₂absorber that works in the long-wave infrared,it finally achieved an absorption rate of over 90%between 8.16?m and 9.61?m,and the FWHM is 2.26?m.This structure can maintain a good absorption shape within the incident light angle of 70^?,and the absorption rate can exceed 70%while maintaining the absorption bandwidth almost unchanged.4.A pure dielectric-SiO₂-medium-metal optical coupling structure of infrared quantum well detector is proposed.Realize electromagnetic wave absorption in the very long wave band(14.5?m).Ultimately obtained light absorbing over 90%.By changing different parameters for calculation and comparison,it can be obtained that the change of the absorption efficiency of the structure and the change of the absorption band are only related to the thickness of the dielectric layer,and the other parameters have little effect on the performance of the structure.Through the electric field enhancement model,we can see that the absorption rate is only affected by the thickness of the dielectric layer and the change of the dielectric constant.