Publications by authors named "Dewang Huo"

6 Publications

  • Page 1 of 1

Broadband Absorption Based on Thin Refractory Titanium Nitride Patterned Film Metasurface.

Nanomaterials (Basel) 2021 Apr 23;11(5). Epub 2021 Apr 23.

Institute of Modern Optics, Department of Physics, Harbin Institute of Technology, Harbin 150001, China.

In this paper, a thin metasurface perfect absorber based on refractory titanium nitride (TiN) is proposed. The size parameter of the metasurface is investigated based on the finite difference time domain method and transfer matrix method. With only a 15-nm-thick TiN layer inside the silica/TiN/silica stacks standing on the TiN substrate, the near-perfect absorption throughout the visible regime is realized. The cross-talk between the upper and lower dielectric layers enables the broadening of the absorption peak. After patterning the thin film into a nanodisk array, the resonances from the nanodisk array emerge to broaden the high absorption bandwidth. As a result, the proposed metasurface achieves perfect absorption in the waveband from 400 to 2000 nm with an average absorption of 95% and polarization-insensitivity under the normal incidence. The proposed metasurface maintains average absorbance of 90% up to 50-degree oblique incidence for unpolarized light. Our work shows promising potential in the application of solar energy harvesting and other applications requiring refractory metasurfaces.
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http://dx.doi.org/10.3390/nano11051092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8145760PMC
April 2021

Polarization-Dependent All-Dielectric Metasurface for Single-Shot Quantitative Phase Imaging.

Nano Lett 2021 May 22;21(9):3820-3826. Epub 2021 Apr 22.

DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Kgs. Lyngby 2800, Denmark.

Phase retrieval is a noninterferometric quantitative phase imaging technique that has become an essential tool in optical metrology and label-free microscopy. Phase retrieval techniques require multiple intensity measurements traditionally recorded by camera or sample translation, which limits their applicability mostly to static objects. In this work, we propose the use of a single polarization-dependent all-dielectric metasurface to facilitate the simultaneous recording of two images, which are utilized in phase calculation based on the transport-of-intensity equation. The metasurface acts as a multifunctional device that splits two orthogonal polarization components and adds a propagation phase shift onto one of them. As a proof-of-principle, we demonstrate the technique in the wavefront sensing of technical samples using a standard imaging setup. Our metasurface-based approach fosters a fast and compact configuration that can be integrated into commercial imaging systems.
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http://dx.doi.org/10.1021/acs.nanolett.1c00190DOI Listing
May 2021

Multi-frequency surface plasmons supported with a nanoscale non-uniform 2D electron gas formed due to a polar catastrophe at the oxide interface, dispersions, diffractions, and beyond.

Nanoscale 2020 Apr;12(13):7082-7097

Institute of Modern Optics, School of Physics, Harbin Institute of Technology, Harbin, 150001, China.

Recently, 2D electron gases (2DEGs) formed at oxide interfaces are drawing increasing attention as they cause a myriad of intriguing phenomena. As ideal platforms in supporting surface plasmon polaritons (SPPs) without metallic constituents, such 2DEGs are favorable in non-linear plasmonics for ultra-low total Joule dissipation. Convincingly, an increase in the interfacial electron density (IIED) formed at the interface of indium-tin-oxide and LiNbO3 composite slab is responsible for a number of interesting phenomena, which are hardly explained with the conventional photorefractive theoretical framework but can be satisfactorily elucidated via SPP excitation and resultant colossal non-linear effects. Since the polar-catastrophe-led IIED is universal to all combinations of highly polar ferroelectric oxides (FOs) and less polar transparent conducting oxides (TCOs), a systematic theoretical treatment of an FO/TCO system is pivotal to a variety of promising applications. In this study, the nanometer scale 2DEG at the FO/TCO interface is illustrated theoretically with the Thomas-Fermi screening picture, by taking into account the spontaneous polarization, along with related boundary conditions. The local plasma frequency of 2DEGs can be increased up to the UV regime for the composite slabs discussed, which are suitable for highly desirable visible applications. The SPP dispersion relationship was given for the 2DEG layer sandwiched between the FO slab and the unmodified TCO layer. To further take the non-uniform nature of IIED into account, dramatic dispersions of dielectric permittivity and index of refraction were simulated with a very broad range, hinting at different ways for meeting phase matching conditions and slowing the light for non-linear plasmonic applications, which are confirmed experimentally.
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http://dx.doi.org/10.1039/c9nr07634dDOI Listing
April 2020

Accumulation-layer hybridized surface plasmon polaritions at an ITO/LiNbO interface.

Opt Lett 2019 Feb;44(4):947-950

To circumvent the hindrance to broad practical applications associated with uses of highly lossy metals in plasmonics, electrostatic modification-based low-loss structures are conceived and demonstrated in supporting surface plasmon polaritions (SPPs). Pairing a highly polar LiNbO (LN) slab with a nonpolar indium-tin-oxide (ITO) thin film, a subnanometer ITO layer was modified into visible SPPs supportive owing to electrostatic screening; yet a theoretical treatment of a sandwiched structure with a sub-nanometer interlayer and an anisotropic substrate is still missing. In this Letter, a hybridized SPP supporting picture was drawn in the ITO/LN system, which agrees well with the 2D diffraction patterns observed out of phase gratings written with two coherent laser beams either of pure-extraordinary, pure-ordinary, or mixed polarizations. This platform of ITO/LN is promising in designing hybridized SPP-based devices in which the parasitic scattering of surface waves may be suppressed greatly.
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http://dx.doi.org/10.1364/OL.44.000947DOI Listing
February 2019

Broadband Perfect Absorber Based on TiN-Nanocone Metasurface.

Nanomaterials (Basel) 2018 Jul 1;8(7). Epub 2018 Jul 1.

Institute of Modern Optics, Department of Physics, Harbin Institute of Technology, Harbin 150001, China.

Based on an integrated array of refractory titanium nitride (TiN), a metasurface perfect absorber (MPA) in the visible-to-near infrared (NIR) band is reported. The systematic and detailed simulation study of the absorption of the MPA is performed with the finite-different time-domain (FDTD) method. Tailoring the structure, the MPA realizes as high an average as 99.6% broadband absorption, ranging from 400 nm to 1500 nm. The broadband perfect absorption can be attributed to localized surface plasmonic resonance (LSPR), excited by the continuous diameter evolution from the apex to the base of the nanocone, and the gap plasmons excited among the nanocones, as well as in the spacer layer at longer wavelengths. Particularly, the coupling of the resonances is essentially behind the broadening of the absorption spectrum. We also evaluated the electric field intensity and polarization-dependence of the nanocone MPA to offer further physical insight into light trapping capability. The MPA shows about 90% average absorption even at an oblique incidence up to 50°, which improves the acceptance capability of light-harvesting system applications. This unique design with the TiN nanocone array/aluminium oxide (Al₂O₃)/TiN structure shows potential in imminent applications in light trapping and thermophotovoltaics.
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http://dx.doi.org/10.3390/nano8070485DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6071003PMC
July 2018

Broadband Perfect Absorber with Monolayer MoS and Hexagonal Titanium Nitride Nano-disk Array.

Nanoscale Res Lett 2017 Dec 25;12(1):465. Epub 2017 Jul 25.

Institute of Modern Optics, Department of Physics, Harbin Institute of Technology, Harbin, 150001, China.

A broadband metamaterial absorber (MA) composed of hexagonal-arranged single-sized titanium nitride (TiN) nano-disk array and monolayer molybdenum disulfide (MoS) is studied using finite-difference time-domain (FDTD) simulations. The structure of TiN nano-disk array/dielectric silica (SiO)/aluminum (Al) is adopted in our design. By optimizing the dimension parameters of the structure, an average absorption of 96.1% is achieved from 400 to 850 nm. In addition, by inserting a monolayer MoS which has high absorption at the short wavelength side underneath the TiN nano-disk array, an average absorption of 98.1% over the entire visible regime from 400 to 850 nm was achieved, with a peak absorption near 100% and absorption over 99% from 475 to 772 nm. Moreover, the absorber presented in this paper is polarization insensitive. This compact and unique design with TiN nano-disk/monolayer MoS/ SiO/Al structure may have great potential for applications in photovoltaics and light trapping.
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http://dx.doi.org/10.1186/s11671-017-2232-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5526828PMC
December 2017