Broadband achromatic polarization insensitive metalens over 950 nm bandwidth in the visible and near-infrared

AbstractOver the past years, broadband achromatic metalenses have been intensively studied due to their great potential for applications in consumer and industry products. Even though significant progress has been made, the efficiency of technologically relevant silicon metalenses is limited by the intrinsic material loss above the bandgap. In turn, the recently proposed achromatic metalens utilizing transparent, high-index materials such as titanium dioxide has been restricted by the small thickness and showed relatively low focusing efficiency at longer wavelengths. Consequently, metalens-based optical imaging in the biological transparency window has so far been severely limited. Herein, we experimentally demonstrate a polarization-insensitive, broadband titanium dioxide achromatic metalens for applications in the near-infrared biological imaging. A large-scale fabrication technology has been developed to produce titanium dioxide nanopillars with record-high aspect ratios featuring pillar heights of 1.5 µm and ~90° vertical sidewalls. The demonstrated metalens exhibits dramatically increased group delay range, and the spectral range of achromatism is substantially extended to the wavelength range of 650–1000 nm with an average efficiency of 77.1%–88.5% and a numerical aperture of 0.24–0.1. This research paves a solid step towards practical applications of flat photonics.

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Graphene-Based Cylindrical Pillar Gratings for Polarization-Insensitive Optical Absorbers

Applied Sciences ◽

10.3390/app9122528 ◽

2019 ◽

Vol 9 (12) ◽

pp. 2528 ◽

Cited By ~ 4

Author(s):

Muhammad Fayyaz Kashif ◽

Giuseppe Valerio Bianco ◽

Tiziana Stomeo ◽

Maria Antonietta Vincenti ◽

Domenico de Ceglia ◽

...

Keyword(s):

Near Infrared ◽

Monolayer Graphene ◽

Geometrical Parameters ◽

Guided Mode ◽

Rigorous Coupled Wave Analysis ◽

Dielectric Gratings ◽

Method Effects ◽

Polarization Insensitive ◽

Rigorous Coupled Wave ◽

Infrared Frequencies

In this study, we present a two-dimensional dielectric grating which allows achieving high absorption in a monolayer graphene at visible and near-infrared frequencies. Dielectric gratings create guided-mode resonances that are exploited to effectively couple light with the graphene layer. The proposed structure was numerically analyzed through a rigorous coupled-wave analysis method. Effects of geometrical parameters and response to the oblique incidence of the plane wave were studied. Numerical results reveal that light absorption in the proposed structure is almost insensitive to the angle of the impinging source over a considerable wide angular range of 20°. This may lead to the development of easy to fabricate and experimentally viable graphene-based absorbers in the future.

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High efficiency focusing vortex generation and detection with polarization-insensitive dielectric metasurfaces

Nanoscale ◽

10.1039/c8nr07480a ◽

2018 ◽

Vol 10 (40) ◽

pp. 19154-19161 ◽

Cited By ~ 44

Author(s):

Kai Ou ◽

Guanhai Li ◽

Tianxin Li ◽

Hui Yang ◽

Feilong Yu ◽

...

Keyword(s):

Near Infrared ◽

High Efficiency ◽

Vortex Beam ◽

Vortex Generation ◽

Polarization Insensitive ◽

Polarization Independent

High-efficiency and polarization-independent focused vortex beam generators and detectors are realized and demonstrated with all dielectric metasurfaces in near-infrared regime.

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Efficient Broadband Truncated-Pyramid-Based Metamaterial Absorber in the Visible and Near-Infrared Regions

Crystals ◽

10.3390/cryst10090784 ◽

2020 ◽

Vol 10 (9) ◽

pp. 784 ◽

Cited By ~ 1

Author(s):

Phuc Toan Dang ◽

Tuan V. Vu ◽

Jongyoon Kim ◽

Jimin Park ◽

Van-Chuc Nguyen ◽

...

Keyword(s):

Communication Systems ◽

Near Infrared ◽

Cell Structure ◽

Single Layer ◽

Normal Incidence ◽

Transverse Magnetic ◽

Metamaterial Absorber ◽

Broadband Absorption ◽

Polarization Insensitive ◽

Truncated Pyramid

We present a design of an ultra-broadband metamaterial absorber in the visible and near- infrared regions. The unit cell structure consists of a single layer of metallic truncated-pyramid resonator-dielectric-metal configuration, which results in a high absorption over a broad wavelength range. The absorber exhibits 98% absorption at normal incidence spanning a wideband range of 417–1091 nm, with >99% absorption within 822–1054 nm. The broadband absorption stability maintains 95% at large incident angles up to 40° for the transverse electric (TE)-mode and 20° for the transverse magnetic (TM)-mode. Furthermore, the polarization-insensitive broadband absorption is presented in this paper by analyzing absorption performance with various polarization angles. The proposed absorber can be applied for applications such as solar cells, infrared detection, and communication systems thanks to the convenient and compatible bandwidth for electronic THz sources.

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Cascaded Nanorod Arrays for Ultrabroadband, Omnidirectional and Polarization-Insensitive Absorption

Applied Sciences ◽

10.3390/app10113878 ◽

2020 ◽

Vol 10 (11) ◽

pp. 3878

Author(s):

Xun Wang ◽

Tian Sang ◽

Honglong Qi ◽

Guoqing Li ◽

Xin Yin ◽

...

Keyword(s):

Wavelength Range ◽

Near Infrared ◽

Structural Parameters ◽

Resonant Cavity ◽

Dielectric Materials ◽

Localized Surface Plasmon ◽

Nanorod Arrays ◽

Absorption Properties ◽

Polarization Insensitive ◽

Absorption Performance

An ultrabroadband, omnidirectional, and polarization-insensitive absorber based on cascaded nanorod arrays (CNAs) is numerically demonstrated, and an average absorptivity of 98.2% with a relative absorption bandwidth (RAB) of 149.8% can be achieved in the 0.38–2.65 μm wavelength range. The proposed CNA-based absorber requires only several pairs of multilayers to achieve excellent absorption performance. More significantly, the physical mechanism for this intriguing ultrabroadband absorption results from the synergistic effect of localized surface plasmon (LSP) and plasmonic resonant cavity (PRC) modes, which is fundamentally different from the tapered metal/dielectric multilayer-based absorbers associated with the slow-light mode. We investigated the absorption properties of the CNA-based metasurface by using the impedance theory, which indicates that the impedance of the structure matches well with the impedance of the free space from the visible to near-infrared wavelength range. In addition, the absorption properties of the CNA-based metasurface are robust to the variation of the structural parameters and the metal/dielectric materials, and ultrabroadband absorption performance can be maintained within 0–60° for both TM and TE modes.

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Wide-angle polarization-insensitive transparency of a continuous opaque metal film for near-infrared light

Optics Express ◽

10.1364/oe.22.006519 ◽

2014 ◽

Vol 22 (6) ◽

pp. 6519 ◽

Cited By ~ 20

Author(s):

Zhengyong Song ◽

Baile Zhang

Keyword(s):

Metal Film ◽

Near Infrared ◽

Infrared Light ◽

Wide Angle ◽

Near Infrared Light ◽

Polarization Insensitive

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Ultra-broadband, lithography-free, omnidirectional, and polarization-insensitive perfect absorber

Scientific Reports ◽

10.1038/s41598-021-84889-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tse-An Chen ◽

Meng-Ju Yub ◽

Yu-Jung Lu ◽

Ta-Jen Yen

Keyword(s):

Mass Production ◽

Near Infrared ◽

Magnesium Fluoride ◽

Perfect Absorber ◽

Plasmonic Resonance ◽

Practical Applications ◽

Narrow Bandwidth ◽

Thermal Emitters ◽

Polarization Insensitive ◽

Color Filters

AbstractPerfect absorbers (PAs) at near infrared allow various applications such as biosensors, nonlinear optics, color filters, thermal emitters and so on. These PAs, enabled by plasmonic resonance, are typically powerful and compact, but confront inherent challenges of narrow bandwidth, polarization dependence, and limited incident angles as well as requires using expensive lithographic process, which limit their practical applications and mass production. In this work, we demonstrate a non-resonant PA that is comprised of six continuous layers of magnesium fluoride (MgF2) and chromium (Cr) in turns. Our device absorbs more than 90% of light in a broad range of 900–1900 nm. In addition, such a planar design is lithography-free, certainly independent with polarization, and presents a further advantage of wide incidence up to 70°. The measured performance of our optimized PA agrees well with analytical calculations of transfer matrix method (TMM) and numerical simulations of finite element method, and can be readily implemented for practical applications.

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Designing polarization insensitive negative index metamaterial for operation in near infrared

Optics Communications ◽

10.1016/j.optcom.2011.12.096 ◽

2012 ◽

Vol 285 (8) ◽

pp. 2195-2200 ◽

Cited By ~ 7

Author(s):

M. Giloan ◽

S. Astilean

Keyword(s):

Near Infrared ◽

Negative Index ◽

Polarization Insensitive

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Ultra-Broadband, Lithography-Free, Omnidirectional, and Polarization-Insensitive Perfect Absorber

10.21203/rs.3.rs-127512/v1 ◽

2020 ◽

Author(s):

Tse-An Chen ◽

Meng-Ju Yub ◽

Yu-Jung Lu ◽

Ta-Jen Yen

Keyword(s):

Mass Production ◽

Near Infrared ◽

Magnesium Fluoride ◽

Perfect Absorber ◽

Plasmonic Resonance ◽

Practical Applications ◽

Narrow Bandwidth ◽

Thermal Emitters ◽

Polarization Insensitive ◽

Color Filters

Abstract Perfect absorbers (PAs) at near infrared allow various applications such as biosensors, nonlinear optics, color filters, thermal emitters and so on. These PAs, enabled by plasmonic resonance, are typically powerful and compact, but confront inherent challenges of narrow bandwidth, polarization dependence, and limited incident angles as well as requires using expensive lithographic process, which limit their practical applications and mass production. In this work, we demonstrate a non-resonant PA that is comprised of six continuous layers of magnesium fluoride (MgF2) and chromium (Cr) in turns. Our device absorbs more than 90% of light in a broad range of 900-1900 nm. In addition, such a planar design is lithography-free, certainly independent with polarization, and presents a further advantage of wide incidence up to 70°. The measured performance of our optimized PA agrees well with analytical calculations of transfer matrix method (TMM) and numerical simulations of finite element method, and can be readily implemented for practical applications.

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