Three-dimensionally reconfigurable focusing of laser by mechanically tunable metalens doublet with built-in holograms for alignment

Autor: Jung Joonkyo, Kim Hyeonhee, Shin Jonghwa
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Nanophotonics, Vol 12, Iss 8, Pp 1373-1385 (2023)
Druh dokumentu: article
ISSN: 2192-8606
2192-8614
2022-0634
DOI: 10.1515/nanoph-2022-0634
Popis: Metalenses have potential to replace various bulky conventional optical elements with ultrathin nanostructure arrays. In particular, active metalenses with reconfigurable focusing capability have attracted considerable interest from the academic and industrial communities. However, their tuning range is currently restricted by limited material properties and fabrication difficulties. Here, a hybrid optical system capable of three-dimensional relocation of a focal spot is proposed and experimentally demonstrated. The system comprises a mechanically actuated passive metalens doublet that can be easily fabricated with commonly available materials and processes. An incident laser can be focused to a desired point in three-dimensional space simply by rotating two metalenses or changing their separation. In addition, exploiting the polarization-multiplexing capability of metasurfaces, a hologram is incorporated to the metalenses to guide rotational and positional alignment of two metasurfaces. The ease of fabrication and alignment provided by this approach could widen its application to many practical fields.
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