Generation of terahertz vector beams using dielectric metasurfaces via spin-decoupled phase control

Nanophotonics

article

Yuehong Xu¹  Weili Zhang²  Huifang Zhang¹  Quan Li³  Xueqian Zhang¹  Quan Xu¹  Wentao Zhang⁴  Cong Hu⁴  Xixiang Zhang⁵  Jiaguang Han¹ 

[1] Center for Terahertz waves and College of Precision Instrument and Optoelectronics Engineering, Tianjin University and the Key Laboratory of Optoelectronics Information and Technology (Ministry of Education);School of Electrical and Computer Engineering, Oklahoma State University;School of Electronic Engineering, Tianjin University of Technology and Education;Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, Guilin University of Electronic Technology;Physical Science and Engineering Division, King Abdullah University of Science and Technology

关键词: all-dielectric metasurface;    radially and azimuthally polarized;    terahertz;    vector vortex beam;    vector Bessel beam;   

DOI  :  10.1515/nanoph-2020-0112

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

Cylindrical vector beams (CVBs), being a special kind of beams with spatially variant states of polarizations, are promising in photonics applications, including high-resolution imaging, plasmon excitation, optical trapping, and laser machining. Recently, generating CVBs using metasurfaces has drawn enormous interest owing to their highly designable, multifunctional, and integratable features. However, related studies remain unexplored in the terahertz regime. Here, a generic method for efficiently generating terahertz CVBs carrying orbital angular momentums (OAMs) is proposed and experimentally demonstrated using transmission-type spatial-variant dielectric metasurfaces, which is realized by designing the interference between the two circularly polarized transmission components. This method is based on spin-decoupled phase control allowed by simultaneously manipulating the dynamic phase and geometric phase of each structure, endowing more degree of freedom in designing the vector beams. Two types of metasurfaces which respectively generate polarization-dependent terahertz vector vortex beams (VVBs) and vector Bessel beams (VBBs) are experimentally characterized. The proposed method opens a new window to generate versatile vector beams, providing new capabilities in developing novel, compact, and high-performance devices applicable to broad electromagnetic spectral regimes.

【 授权许可】

CC BY