Design method of phase-controllable ultrathin sub-terahertz vortex vector light beam generator

Abstract

The invention discloses a design method of a phase-controllable ultrathin sub-terahertz vortex vector light beam generator. The phase-controllable ultrathin sub-terahertz vortex vector light beam generator is composed of a top metal microstructure, a dielectric layer and a bottom metal gate. The design method of the phase-controllable ultrathin sub-terahertz vortex vector light beam generator comprises the following steps of: transversely dividing the phase-controllable ultrathin sub-terahertz vortex vector light beam generator into eight sectors; and properly selecting the unit shape and sizeof the top metal microstructure and the gate orientation of the bottom metal gate in each sector, and providing pPhase and polarization distributions that vary with the sectors, wherein the bottom layer metal gate mainly controls the polarization direction, the top layer metal microstructure mainly controls the transmission phase, and a Fabry-Perot cavity is formed between the bottom layer metalgate and the top layer metal microstructure, so that the polarization conversion efficiency can be improved, the change range of the transmission phase can be enlarged, and the vortex vector light beam with any topological charge number can be generated. The design method provided by the invention is intuitive and simple, the device structure is compact, the linear polarization terahertz source can be directly converted into high-quality special structure optical radiation, and the design method has important application prospect in a terahertz imaging system.

Description

technical field [0001] The invention belongs to the field of new artificial electromagnetic materials and terahertz science and technology, and specifically relates to a design method of a high-efficiency, ultra-thin, transmissive vortex vector beam generator capable of generating arbitrary topological charge numbers. Background technique [0002] Located at 0.1-0.3THz (1THz=10 12 Hz) range, due to its small photon energy, no damage to biological tissues, and strong penetrating ability to textiles, plastics, etc., it has extremely high scientific research value and importance in the fields of biomedical imaging and security imaging. Wide application prospects. Research on compact vortex vector beam generators can provide high-quality light sources for sub-terahertz imaging systems, which are expected to break through the diffraction limit and improve imaging resolution. Common vector beams include radial polarization and angular polarization, while vortex vector beams are ...

AI Technical Summary

Problems solved by technology

[0005] Purpose of the invention: The purpose of the present invention is to provide a design method for a phase-controllable ultra-thin sub-subahertz vortex vector beam generator, which solves the problem that the vortex vector beam with any topological charge number cannot be generated in the existing solutions, and the The design uses a more common linearly polarized light source, and the thickness is only 1 / 14 of the wavelength, providing a compact and flexible design solution for the generation of structured beams in the sub-terahertz band

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