Lithography-free metasurfaces composed of a nano-layered stack of materials are attractive not only due to their optical properties but also by virtue of fabrication simplicity and cost reduction of devices based on such structures. We demonstrate a multi-layer metasurface with engineered electromagnetic absorption in the mid-infrared (MIR) wavelength range. Characterisation of thin SiO$_2$ and Si films sandwiched between two Au layers by way of experimental absorption and thermal radiation measurements as well as finite difference time domain (FDTD) numerical simulations is presented. Comparison of experimental and simulation data of optical properties of multilayer metasurfaces show guidelines for the absorber/emitter applications.
Thermo-optical properties of the nanodisc and metal hole array plasmonic perfect absorber (PPA) metasurfaces were designed and characterised at midinfrared wavelengths. Both, light emitter and detector systems are highly thought after for the future sensor networks in the internet-of-things for various spectral domains. Reciprocity of the absorbance and emittance is shown experimentally, i.e., the PPAs are following Kirchhoff's law where the patterns exhibiting a strong optical absorption were found enhanced thermal radiation. Design principles and scaling for photo-thermal conversion are disc…
We demonstrate the fabrication of diffraction-limited dielectric metasurface lenses for NIR by use of standard industrial high throughput silicon processing techniques: UV Nano Imprint Lithography (UV-NIL) combined with continuous Reactive Ion Etching (RIE) and pulsed Bosch Deep Reactive Ion Etching (DRIE). As the research field of metasurfaces moves towards applications these techniques are relevant as potential replacements of commonly used cost-intensive fabrication methods utilizing Electron Beam Lithography. We show that washboard-type sidewall surface roughness arising from the Bosch DRI…
Single-Step Grayscale Lithography of Multi-Depth Mie Void Metasurfaces
Institute of Applied Physics, The Faculty of Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem（希伯来大学应用物理学院科学系纳米科学与纳米技术中心）；Singapore-HUJ Alliance for Research and Enterprise (SHARE), The Smart Grippers for Soft Robotics (SGSR) Programme, Campus for Research Excellence and Technological Enterprise (CREATE)（新加坡-希伯来大学研究与企业联盟（SHARE），软体机器人智能夹爪（SGSR）项目，卓越研究与技术企业园区（CREATE））
Scalable Fabrication of Thermally Reconfigurable Ge Metasurfaces Using Stencil Lithography for Mid-Infrared Molecular Sensing
Department of Biomedical Engineering, University of Wisconsin-Madison（威斯康星大学麦迪逊分校生物医学工程系）；Department of Electrical and Computer Engineering, University of Wisconsin–Madison（威斯康星大学麦迪逊分校电气与计算机工程系）；Department of Physics, Faculty of Science, Istanbul University（伊斯坦布尔大学理学院物理系）
Metalenses, which exhibit superior light-modulating performance with sub-micrometer-scale thicknesses, are suitable alternatives to conventional bulky refractive lenses. However, fabrication limitations, such as a high cost, low throughput, and small patterning area, hinder their mass production. Here, we demonstrate the mass production of low-cost, high-throughput, and large-aperture visible metalenses using an argon fluoride immersion scanner and wafer-scale nanoimprint lithography. Once a 12-inch master stamp is imprinted, hundreds of centimeter-scale metalenses can be fabricated. To enhanc…
Achieving an electrically tunable phased array optical antenna surface has been a principal challenge in the field of metasurfaces. In this letter, we demonstrate a device platform for achieving reconfigurable control over the resonant wavelength of a subwavelength optical antenna through free-carrier injection. We engineer and grow, using molecular beam epitaxy, a heterostructure of In1-xAlxAs/InAs/AlyGa1-ySb layers designed to achieve large amplitude and phase modulation of light by maximizing the refractive index change in regions of resonant field enhancement The p-i-n layers are grown on …
The spectral numerical mode-matching (SNMM) method is developed to simulate the 3D layered multi-region structures. The SNMM method is a semi-analytical solver having the properties of dimensionality reduction to reduce computational costs; it is especially useful for microwave and optical integrated circuits where fabrication is often done in a layered structure. Furthermore, at some layer interfaces, very thin surfaces such as good conductor surfaces and metasurfaces can be deposited to achieve desired properties such as high absorbance and/or anomalous reflection/refraction. In this work, t…
Metamaterials are composed of periodic subwavelength metal/dielectric structures that resonantly couple to the electric and/or magnetic components of the incident electromagnetic fields, exhibiting properties that are not found in nature. Planar metamaterials with subwavelength thickness, or metasurfaces, consisting of single-layer or few-layer stacks of planar structures, can be readily fabricated using lithography and nanoprinting methods, and the ultrathin thickness in the wave propagation direction can greatly suppress the undesirable losses. Metasurfaces enable a spatially varying optical…
Metalens as one of the most popular applications of emmerging optical metasurfaces has raised widspread interest recently. With nano structures fully controlling phase, polarization and transmission, metalens has achieved comparable performance of commercial objective lenses. While recent studies seeking for the accomplishment of traditional focusing behaviors through metalens are successful, inthis work, we have discovered that instead of focusing light to a point, metasurface further enables shaping the focus into a flexibly designed pattern, with more promises and potentials. New mechanism …
Surfaces covered with layers of ultrathin nanoantenna structures, so-called metasurfaces, have recently been proven capable of completely controlling phase of light. Metalenses have emerged from the advance in the development of metasurfaces providing a new basis for recasting traditional lenses into thin, planar optical components capable of focusing light. The lens made of arrays of plasmonic gold nanorods were fabricated on a glass substrate by using electron beam lithography. A 1064 nm laser was used to create a high intensity circularly polarized light focal spot through metalens of focal…
