Metasurface-based varifocal Alvarez lens at microwave frequencies.
Opt Express
; 32(2): 2058-2066, 2024 Jan 15.
Article
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| MEDLINE
| ID: mdl-38297743
ABSTRACT
Lenses with a tunable focus are highly desirable but remain a challenge. Here, we demonstrate a microwave varifocal meta-lens based on the Alvarez lens principle, consisting of two mechanically movable tri-layer metasurface phase plates with reversed cubic spatial profiles. The manufactured multilayer Alvarez meta-lens enables microwave beam collimation/focusing at frequencies centered at 7.5 GHz, and shows one octave focal length tunability when transversely translating the phase plates by 8 cm. The measurements reveal a gain enhancement up to 15 dB, 3-dB beam width down to 3.5∘, and relatively broad 3-dB bandwidth of 3 GHz. These advantageous characteristics, along with its simplicity, compactness, and lightweightness, make the demonstrated flat Alvarez meta-lens suitable for deployment in many microwave systems.
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MEDLINE
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En
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Opt Express
Asunto de la revista:
OFTALMOLOGIA
Año:
2024
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Article