Abstract
The applications of terahertz (THz) technology can be greatly extended using non-diffractive beams with unique field distributions and non-diffractive transmission characteristics. Here, we design and experimentally demonstrate a set of dual non-diffractive THz beam generators based on an all-dielectric metasurface. Two kinds of non-diffractive beams with dramatically opposite focusing properties, Bessel beam and abruptly autofocusing (AAF) beam, are considered. A Bessel beam with longdistance non-diffractive characteristics and an AAF beam with low energy during transmission and abruptly increased energy near the focus are generated for x- and y-polarized incident waves, respectively. These two kinds of beams are characterized and the results agree well with simulations. In addition, we show numerically that these two kinds of beams can also carry orbital angular momentum by further imposing proper angular phases in the design. We believe that these metasurface-based beam generators have great potential use in THz imaging, communications, non-destructive evaluation, and many other fields. [Figure not available: see fulltext.].
| Original language | English (US) |
|---|---|
| Journal | Frontiers of Optoelectronics |
| DOIs | |
| State | Published - Dec 23 2020 |
Bibliographical note
KAUST Repository Item: Exported on 2021-01-28Acknowledged KAUST grant number(s): OSR-2016-CRG5-2950
Acknowledgements: This work was funded by the National Key Research and Development Program of China (No. 2017YFA0701004), the National Natural Science Foundation of China (Grant Nos. 61935015, 61875150, 61605143, 61735012, 61722509, and 61871212), Tianjin Municipal Fund for Distinguished Young Scholars (No. 18JCJQJC45600), and King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) (No. OSR-2016-CRG5-2950).