Dynamic Focusing with High-Quality-Factor Metalenses

Metasurface lenses provide an ultrathin platform in which to focus light, but weak light–matter interactions limit their dynamic tunability. Here we design submicron-thick, ultrahigh quality factor (high-Q) metalenses that enable dynamic modulation of the focal length and intensity. Using full-field...

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Bibliographic Details
Published in:Nano letters 2020-07, Vol.20 (7), p.5127-5132
Main Authors: Klopfer, Elissa, Lawrence, Mark, Barton, David R, Dixon, Jefferson, Dionne, Jennifer A
Format: Article
Language:English
Subjects:
high-Q
MATERIALS SCIENCE
metalens
metasurface
metasurface modulation
nanophotonics
nonlinearities
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Summary:Metasurface lenses provide an ultrathin platform in which to focus light, but weak light–matter interactions limit their dynamic tunability. Here we design submicron-thick, ultrahigh quality factor (high-Q) metalenses that enable dynamic modulation of the focal length and intensity. Using full-field simulations, we show that quality factors exceeding 5000 can be generated by including subtle, periodic perturbations within the constituent Si nanoantennas. Such high-Q resonances enable lens modulation based on the nonlinear Kerr effect, with focal lengths varying from 4 to 6.5 μm and focal intensities decreasing by half as input intensity increases from 0.1 to 1 mW/μm2. We also show how multiple high-Q resonances can be embedded in the lens response through judicious placement of the perturbations. Our high-Q lens design, with quality factors 2 orders of magnitude higher than existing lens designs, provides a foundation for reconfigurable, multiplexed, and hyperspectral metasurface imaging platforms.
ISSN:1530-6984
1530-6992
DOI:10.1021/acs.nanolett.0c01359