Generation of Terahertz Vortices Using Metasurface With Circular Slits

Author

Hailong Zhou ; Jianji Dong ; Siqi Yan ; Yifeng Zhou ; Xinliang Zhang

Author_Institution

Wuhan Nat. Lab. for Optoelectron., Huazhong Univ. of Sci. & Technol., Wuhan, China

Volume

6

Issue

6

fYear

2014

fDate

Dec. 2014

Firstpage

1

Lastpage

7

Abstract

We propose a metal device containing circular slits to generate a terahertz (THz) orbital angular momentum beam with numerical simulations. The estimation of the polarization extinction ratio is above 20 dB over the bandwidth ranging from 0.3 to 3 THz, and a mode purity of TC = 1 or -1 is close to 1 over a wide bandwidth range, except for the area near the deteriorated valley. We analyze the OAM spectrum and find that the main noise comes from an OAM mode of TC = -3 or 3. When multiple concentric circular slits are employed, a larger transmittance is obtained without the sacrifice of mode purity. The design of such a device is simple with a size of micrometer order, revealing an option to generate a broadband THz vortex beam.

Keywords

angular momentum; laser beams; micro-optics; microwave photonics; optical design techniques; optical metamaterials; optical noise; optical vortices; bandwidth 0.3 THz to 3 THz; circular slits; metasurface; mode purity; noise; polarization extinction ratio; terahertz orbital angular momentum beam; terahertz vortices generation; transmittance; Bandwidth; Electric fields; Films; Graphical models; Metals; Noise; Vectors; Orbital angular momentum; metamaterials; terahertz;

fLanguage

English

Journal_Title

Photonics Journal, IEEE

Publisher

ieee

ISSN

1943-0655

Type

jour

DOI

10.1109/JPHOT.2014.2363424

Filename

6926759