Single-step manufacturing of hierarchical dielectric metalens in the visible

Abstract

Metalenses have shown a number of promising functionalities that are comparable with conventional refractive lenses. However, current metalenses are still far from commercialization due to the formidable fabrication costs. Here, we demonstrate a low-cost dielectric metalens that works in the visible spectrum. The material of the metalens consists of a matrix-inclusion composite in which a hierarchy satisfies two requirements for the single-step fabrication; a high refractive index and a pattern-transfer capability. We use a UV-curable resin as a matrix to enable direct pattern replication by the composite, and titanium dioxide nanoparticles as inclusions to increase the refractive index of the composite. Therefore, such a dielectric metalens can be fabricated with a single step of UV nanoimprint lithography. An experimental demonstration of the nanoparticle composite-based metalens validates the feasibility of our approach and capability for future applications. Our method allows rapid replication of metalenses repeatedly and thereby provides an advance toward the use of metalenses on a commercial scale.

Scalable and High-Throughput Top-Down Manufacturing of Optical Metasurfaces

“…The SEM images of (i) master mold, (ii) soft mold, and (iii) final metalens. All scale bars are 100 μm [2]. (b) (i) Mechanism of the DNI process, (ii) a rigid nanograting mold, (iii) a inscribed nanopattern on a flexible substrate, (iv) the SEM image of a nanopattern using the DNI.…”

“…(i) Schematics of laser-scanning replication, (ii) the SEM image and (iii) the atomic force microscope profile of the mold [192]. Reproduced with permission from (a) [2]; CC by 4.0, (b) [185]; American Chemical Society, 2019, and (c) [192]; Elsevier B.V., 2014.…”

“…The porous titania resonators have multiple applications including tuning the sharp bandpass filter (up to 40 dB rejection ratio), gas or liquid sensor, and dynamic color changing structure. To achieve both the low cost and high refractive index nanopattern, Yoon and Kim et al suggest the facile metamaterial manufacturing process based on the resin with the titania nanoparticles [ 2 , 171 ]. Combining the UV-curable resin and nanoparticles can increase the refractive index without secondary operation ( Figure 10 a).…”

“…Metasurfaces, on the other hand, have been considered as a promising candidate for the replacement of conventional lenses. They have been applied as high-resolution ultrathin lenses [ 1 , 2 ], as well as superlenses and hyperlenses that overcome diffraction limits [ 3 , 4 , 5 ]. Metasurfaces can also play the role of color filters, selectively transmitting or reflecting the specific wavelengths of incident light to produce the desired colors [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”

Critical Layer Thickness Analysis of Vertically Stacked Hyperbolic Metamaterials for Effective Negative Refraction Generation

“…Metamaterials have been widely studied because of their extraordinary characteristics and potentials in numerous applications such as negative refraction, [ 1–10 ] super‐resolution imaging, [ 11,12 ] perfect absorbers, [ 13,14 ] artificial chirality, [ 15,16 ] invisibility cloaking, [ 17,18 ] and metalens. [ 19–21 ] Hyperbolic metamaterials (HMMs) are ones of the most unusual classes of metamaterials because of its indefinite hyperbolic dispersion. [ 22–24 ] The unique dispersion characteristics of HMMs have been exploited to realize negative refraction [ 3,25–30 ] and sub‐wavelength imaging.…”