Achromatic Varifocal Metalens for the Visible Spectrum

Abstract

Metasurface optics provide an ultrathin alternative to conventional refractive lenses. A present challenge is in realizing metasurfaces that exhibit tunable optical properties and achromatic behavior across the visible spectrum. Here, we report the design, fabrication, and characterization of metasurface lenses (“metalenses”) that use asymmetric titanium dioxide (TiO2) nanostructures to induce a polarization-dependent optical response. By rotating the polarization of linearly polarized input light, the focal length of a 40 μm diameter metalens is tuned from 220 to 550 μm. We show that imparting a wavelength-dependent polarization rotation on incident light enables achromatic focusing over a wide band of the visible spectrum, 483–620 nm. We use this property to demonstrate varifocal color imaging with white light from a halogen source. We also discuss how tunable achromatic metalenses may be useful for display applications.

Cubic-Phase Metasurface for Three-Dimensional Optical Manipulation

“…Moreover, our metasurface based on beam shaper can be directly integrated with fiber optic probes and microfluidic devices [ 60 , 62 ]. Moreover, a tunable metasurface based on beam shaper can be designed to adjust trapping potentials along the axial direction [ 63 , 64 , 65 ]. Our technique is not limited only to Airy beams, and other exotic light beams can be created from a metasurface with different operation wavelengths, without any additional optical components.…”

Principles, Functions, and Applications of Optical Meta‐Lens

“…For the continuous variation of the focal length, Aiello et al. [ 133 ] demonstrated a varifocal meta‐lens based on the rotational polarization of linearly polarized incident light, as shown in Figure 11b. The focal length can be tuned from 220 to 550 µm.…”

“…Reproduced with permission. [ 133 ] Copyright 2019, American Chemical Society. c) Unit cell structure for electrically modulated meta‐lens combined with TN LCs.…”

“…[78] The meta-lens switched the focal length between two focal planes by simply changing the linear polarizations of the incident light (Figure 11a). For the continuous variation of the focal length, Aiello et al [133] demonstrated a varifocal meta-lens based on the rotational polarization of linearly polarized incident light, as shown in Figure 11b. The focal length can be tuned from 220 to 550 µm.…”

High-Sensitivity High-Throughput Detection of Nucleic Acid Targets on Metasurface Fluorescence Biosensors

“…Originally, metasurfaces have diverse potential and have exhibited various applications, stemming from their designs with large degree of freedom [ 14 , 15 , 16 ]. Most of metasurfaces intended to manipulate light waves for particular purposes such as focusing [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ], polarization/phase control [ 24 , 25 , 26 , 27 , 28 , 29 ], perfect light absorption [ 30 , 31 , 32 , 33 , 34 , 35 ], and so on. The application of metasurfaces for FL enhancement has been tried in numerous studies; only a very small portion of the studies exceptionally reported prominent success in the very large FL-intensity enhancement more than 1000-fold to reference non-enhancing substrates [ 10 , 11 , 36 , 37 , 38 , 39 , 40 , 41 ].…”