Affiliation of Author(s):[1]Southeast Univ, Dept Radio Engn, State Key Lab Millimeter Waves, Nanjing 210096, Jiangsu, Peoples R China;[2]Cooperat Innovat Ctr Terahertz Sci, Chengdu 610054, Peoples R China;[3]Nankai Univ, Minist Educ, Key Lab Opt Informat Sci & Technol, Inst Modern Opt, Tianjin 300071, Peoples R China;[4]Fudan Univ, Dept Phys, Minist Educ, State Key Lab Surface Phys,Key Lab Micro & Nano P, Shanghai 200433, Peoples R China;[5]Univ Elect Sci & Technol China, State Key Lab Elect Films & Integrated Devices, Chengdu 610054, Peoples R China;[6]Nanjing Univ, Sch Elect Sci & Engn, RISE, Nanjing 210093, Jiangsu, Peoples R China;[7]Tianjin Univ, Coll Precis Instrument & Optoelect Engn, Inst Lasers & Optoelect, Tianjin 300072, Peoples R China
Journal:LIGHT-SCIENCE & APPLICATIONS
Key Words:coding; diffusion; metasurface; terahertz waves
Abstract:The terahertz region is a special region of the electromagnetic spectrum that incorporates the advantages of both microwaves and infrared light waves. In the past decade, metamaterials with effective medium parameters or gradient phases have been studied to control terahertz waves and realize functional devices. Here, we present a new approach to manipulate terahertz waves by using coding metasurfaces that are composed of digital coding elements. We propose a general coding unit based on a Minkowski closed-loop particle that is capable of generating 1-bit coding (with two phase states of 0 and 180 degrees), 2-bit coding (with four phase states of 0, 90 degrees, 180 degrees, and 270 degrees), and multi-bit coding elements in the terahertz frequencies by using different geometric scales. We show that multi-bit coding metasurfaces have strong abilities to control terahertz waves by designing-specific coding sequences. As an application, we demonstrate a new scattering strategy of terahertz waves-broadband and wide-angle diffusion-using a 2-bit coding metasurface with a special coding design and verify it by both numerical simulations and experiments. The presented method opens a new route to reducing the scattering of terahertz waves.
Document Type:Article
Volume:4
ISSN No.:2047-7538
Translation or Not:no