Dynamically controlled nanofocusing metalens based on graphene-loaded aperiodic silica grating arrays

A new plasmonic nanofocusing metalens based on aperiodic silica grating arrays was designed and investigated. Assisted by the graphene surface plasmon, the infrared polarized light can be focused in a nanospot with a dynamically controlled focal length by varying the dielectric strip width or the gr...

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Bibliographic Details
Published in:Optics express 2022-02, Vol.30 (4), p.5304-5313
Main Authors: Lu, Liu, Wang, Chenyang, Ngiejungbwen, Looh Augustine, Zhang, Liang, Zhao, Tiantian, Chen, Daifen, Ren, Xifeng
Format: Article
Language:English
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Summary:A new plasmonic nanofocusing metalens based on aperiodic silica grating arrays was designed and investigated. Assisted by the graphene surface plasmon, the infrared polarized light can be focused in a nanospot with a dynamically controlled focal length by varying the dielectric strip width or the graphene Fermi level E . For instance, with λ  = 8 µm and E at 0.3, 0.6 and 0.9 eV, focal lengths of 4.5, 3.8 and 3.5 µm with its corresponding FWHM of 64, 232 and 320 nm, respectively, can be realized. The variation of the focusing efficiency with respect to the incident wavelength and the Fermi level were also investigated. The results of theoretical analysis based on light differential equations agree well with the finite element analysis simulation, which further validate the model.
ISSN:1094-4087
1094-4087
DOI:10.1364/OE.451231