Efficient generation of vectorial terahertz beams using surface-wave excited metasurfaces
利用表面波激发的超表面高效生成矢量太赫兹光束
表面波で励起された超表面を用いたベクトルテラヘルツビームの効率的な生成
표면파 여기 메타표면을 이용한 벡터 테라헤르츠 빔의 효율적 생성
Generación eficiente de haces vectoriales de terahertz en supersuperficies estimuladas por ondas superficiales
Génération efficace de faisceaux Térahertz vectoriels grâce à l'Hypersurface excitée par les ondes de surface
Высокоэффективное формирование векторного терагерцового луча с помощью надповерхностных волн
Zhuo Wang ¹, Weikang Pan ², Yu He ¹, Zhiyan Zhu ², Xiangyu Jin ², Muhan Liu ², Shaojie Ma ², Qiong He ¹ ³, Shulin Sun ² ³ ⁴, Lei Zhou ¹ ³
¹ State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, China
中国 上海 复旦大学应用表面物理国家重点实验室 微纳光子结构教育部重点实验室
² Shanghai Engineering Research Centre of Ultra Precision Optical Manufacturing, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China
中国 上海 复旦大学信息科学与工程学院光科学与工程系 上海超精密光学制造工程技术研究中心
³ Shanghai Key Laboratory of Metasurfaces for Light Manipulation, Shanghai 200433, China
中国 上海 上海市超构表面光场调控重点实验室
⁴ Yiwu Research Institute of Fudan University, Chengbei Road, Yiwu City 322000, China
中国 义乌 复旦大学义乌研究院
On-chip devices for generating pre-designed vectorial optical fields (VOFs) under surface wave (SW) excitations are highly desired in integrated photonics. However, conventional devices are usually of large footprints, low efficiencies, and limited wave-control capabilities. Here, we present a generic approach to design ultra-compact on-chip devices that can efficiently generate pre-designed VOFs under SW excitations, and experimentally verify the concept in terahertz (THz) regime.
We first describe how to design SW-excitation metasurfaces for generating circularly polarized complex beams, and experimentally demonstrate two meta-devices to realize directional emission and focusing of THz waves with opposite circular polarizations, respectively. We then establish a systematic approach to construct an integrated device via merging two carefully designed metasurfaces, which, under SW excitations, can separately produce pre-designed far-field patterns with different circular polarizations and generate target VOF based on their interference.
As a proof of concept, we demonstrate experimentally a meta-device that can generate a radially polarized Bessel beam under SW excitation at ~0.4 THz. Experimental results agree well with full-wave simulations, collectively verifying the performance of our device. Our study paves the road to realizing highly integrated on-chip functional THz devices, which may find many applications in biological sensing, communications, displays, image multiplexing, and beyond.
