All-dielectric polarization beam splitting metamaterial device and parameter calculation method thereof

Abstract

The invention discloses a parameter calculation method for an all-dielectric polarization beam splitting metamaterial device, and the method comprises the steps: determining the period of a grating, and enabling the grating to only have zero-stage diffraction and -1-stage diffraction; obtaining an intrinsic equation of terahertz wave diffraction in the grating area based on a Helmholtz equation; solving the intrinsic equation to obtain the equivalent refractive indexes of the first two Bloch modes propagated in the grating; based on the Mach-Zehnder interferometer principle, obtaining the approximate function relationship between the diffraction efficiency of the two Bloch modes and the grating depth; and giving a duty ratio to obtain the grating depth when the 0-stage or -1-stage diffraction efficiency of the grating reaches the maximum. The invention further discloses an all-dielectric polarization beam splitting metamaterial device. According to the parameter calculation method, a simplified modal method is adopted, the calculation method is simple, and the calculation amount is small. The all-dielectric polarization beam splitting metamaterial device is simple to process, incident terahertz waves of different polarizations can be diffracted to different directions, and high efficiency is achieved.

Description

technical field [0001] The invention relates to a design method of a polarization beam splitting metamaterial device, in particular to an all-dielectric polarization beam splitting metamaterial device and a parameter calculation method thereof. Background technique [0002] Currently, terahertz waves are electromagnetic waves with frequencies between 0.1 THz and 10 THz. A long time ago, human exploration and application of light waves and microwaves were very mature, but it was not until more than 20 years ago that humans gradually began to explore terahertz waves in depth. In recent years, due to terahertz waves in spectroscopy, imaging, Various fields such as quality control and communication have a wide range of functions. Terahertz waves and related technologies have received more and more attention, especially the generation and detection technologies of terahertz waves and the development and manufacture of terahertz functional devices. [0003] Many applications of t...

AI Technical Summary

Problems solved by technology

After decades of research, the grating theory has been very mature. The efficiency of each diffraction order of the grating can be accurately calculated by using the strict coupled wave theory and the time domain finite difference method. The strict coupled wave method uses Fourier expansion to expand the electromagnetic field inside the grating The superposition of a certain number of plane waves with different frequencies is generated, and the diffraction efficiency of each diffraction order of the grating is obtained by solving it. Generally speaking, in order to accurately calculate the diffraction efficiency of the grating, it is necessary to calculate up to the first 20 plane waves, so the calculation is extremely cumbersome. Only Ability to use computer calculations to obtain numerical solutions

Strict coupled-wave theory and finite-difference time-domain method have the disadvantages of large amount of calculation, and the analytical solution of grating diffraction efficiency cannot be obtained, which is not conducive to reverse design.

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