Investigation Of Polarization Properties Of Dielectric/Hyperbolic Materials

In the field of electromagnetism,how to effectively regulate the properties of electromagnetic fields has been a hot topic,the regulation of electromagnetic field properties by traditional optical devices must be affected by the volume and power consumption of the devices themselves,so it is difficult to realize miniaturization and integration.The appearance of metasurface breaks the limitation of traditional period and provides a new idea for the study of electromagnetic field properties.Metasurface structure is a two-dimensional artificial material composed of subwavelength structural units,which can produce effective regulation in electromagnetic field phase,electric field amplitude,polarization properties and so on.This paper mainly uses theoretical calculation and the simulation method of finite element commercial software COMSOL Multiphysics to calculate the dielectric constant form under different angle parameters of hBN optical axis and incident surface and to study the transmittance reflectivity of the film with different parameters.This paper designs the H’film hBN the transmission polarization control metasurface and theSiO₂/hBN transreflective polarization control metasurface,studies the transmission reflection property,the polarization property and the light field distribution,looks forward to the future to provide the feasible design plan to the electromagnetic field control optical device processing,the main research content is as follows:1.Hexagonal boron nitride（hBN）is a kind of uniaxial isotropic crystal with dielectric constant having a transverse element and a longitudinal one.Simulation calculation hBN the direction of the dielectric constant optical axis x the axis in the spindle coordinate system,the dielectric constant form is calculated by changing the angle between the optical axis and the incident plane,and the simulation calculation is carried out by using the COMSOL.The ratio of transmittivity and reflectivity of hBN film under different parameters is laid for the next metasurface simulation calculation.2.Based on the properties of electric field excitation of hyperbolic materials hexagonal boron nitride（hBN）and’H’type structure,a single-layer’H’type groove structure polarization control metasurface is designed.This research used the characteristics of the hBN dielectric constant with frequency and the adjustable optical axis to study the influence of parameters such as the angle between the hBN axis and the surface on the ratio of transmittivity and reflectivity and polarization conversion.The incident wave was designed as x polarized light,the excitation of y polarized light transmitted by the metasurface under different parameters was simulated and the polarization conversion rate（PCR）was obtained.3.Based on SiO₂ and ’H’type thin film hBN metasurface,the polarimetric control ofSiO₂/hBN transreflective polarization control metasurface was designed.The transmittance and reflectivity of theSiO₂/hBN/’H’composite structure are calculated by COMSOL simulation.Based on the results,the reflectance PCR and transmission PCR of the metasurface are calculated respectively.It was calculated that the peak value of reflectance polarization conversion reaches 100%,that is,PCR=1,the peak value of transmission polarization conversion not only reaches 100%,but also has a wider frequency range of high PCR,and the application on optical devices is stronger.