Mid-infrared polarization-controlled broadband achromatic metadevice.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32917714.
- Also identified by DOI 10.1126/sciadv.abc0711 and PMC identifier 7486104.
- Licence recorded as CC BY-NC.
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Abstract
Metasurfaces provide a compact, flexible, and efficient platform to manipulate the electromagnetic waves. However, chromatic aberration imposes severe restrictions on their applications in broadband polarization control. Here, we propose a broadband achromatic methodology to implement polarization-controlled multifunctional metadevices in mid-wavelength infrared with birefringent meta-atoms. We demonstrate the generation of polarization-controlled and achromatically on-axis focused optical vortex beams with diffraction-limited focal spots and switchable topological charge (<i>L</i> <sup>∥</sup> = 0 and <i>L</i> <sup>⊥</sup> = 2). Besides, we further implement broadband achromatic polarization beamsplitter with high polarization isolation (extinction ratio up to 21). The adoption of all-silicon configuration not only facilitates the integration with CMOS technology but also endows the polarization multiplexing meta-atoms with broad phase dispersion coverage, ensuring the large size and high performance of the metadevices. Compared with the state-of-the-art chromatic aberration-restricted polarization-controlled metadevices, our work represents a substantial advance and a step toward practical applications.