Achromatic Metalens over 60 nm Bandwidth in the Visible and Metalens with Reverse Chromatic Dispersion
| Autor: | Aun Zaidi, Zhujun Shi, Wei Ting Chen, Mohammadreza Khorasaninejad, Alexander Y. Zhu, Vyshakh Sanjeev, Federico Capasso |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Photoluminescence Bioengineering 02 engineering and technology Dielectric 01 natural sciences law.invention 010309 optics Optics law 0103 physical sciences Focal length General Materials Science Spectroscopy Nanopillar business.industry Mechanical Engineering Bandwidth (signal processing) General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Wavelength Achromatic lens Optoelectronics 0210 nano-technology business |
| Zdroj: | Nano Letters. 17:1819-1824 |
| ISSN: | 1530-6992 1530-6984 |
| Popis: | In this Letter, we experimentally report an achromatic metalens (AML) operating over a continuous bandwidth in the visible. This is accomplished via dispersion engineering of dielectric phase shifters: titanium dioxide nanopillars tiled on a dielectric spacer layer above a metallic mirror. The AML works in reflection mode with a focal length independent of wavelength from λ = 490 to 550 nm. We also design a metalens with reverse chromatic dispersion, where the focal length increases as the wavelength increases, contrary to conventional diffractive lenses. The ability to engineer the chromatic dispersion of metalenses at will enables a wide variety of applications that were not previously possible. In particular, for the AML design, we envision applications such as imaging under LED illumination, fluorescence, and photoluminescence spectroscopy. |
| Databáze: | OpenAIRE |
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