Papers by Haroldo Hattori
Nanoscale, 2022
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In general, noble metals based nano-antennas cannot work at high power applications such as heat ... more In general, noble metals based nano-antennas cannot work at high power applications such as heat resisted magnetic recording, solar thermo-photovoltaics, and nano-scale heat transfer systems. These antennas are prone to being damaged at sufficiently high energy density due to their small footprint and low Tamman temperature. This paper proposes tungsten refractory plasmonic material based nano-antennas as an alternative gold nano-antennas: we show that the antennas can handle 300 times higher fluence than gold (Au) counterpart. In addition, it can achieve 7.22 higher magnitude of electric field intensity than gold antennas.
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We report the electrical control of the optical attenuation by a manganese dioxide (MnO 2 ) metas... more We report the electrical control of the optical attenuation by a manganese dioxide (MnO 2 ) metasurface. The attenuation is varied by 25% with the change of current of 5.33 μA. The device shows the potential of this material in tunable devices.
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Nano-antennas cannot handle high energy density (fluences) due to their small footprint. In this ... more Nano-antennas cannot handle high energy density (fluences) due to their small footprint. In this paper, we propose chromium based nano-antenna and experimentally show that it can handle 110 times higher fluence than gold (Au) counterpart without a significant reduction in their electrical field enhancement capacities.
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This paper discusses the different techniques available for fabricating tapered structures based ... more This paper discusses the different techniques available for fabricating tapered structures based on the sol-gel deposition process. Experimental difficulties are examined and conclusions drawn leading to the best approach for a future device
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We propose a post-processing approach for tuning terahertz metamaterials by modifying the couplin... more We propose a post-processing approach for tuning terahertz metamaterials by modifying the coupling between two metamaterial layers. We demonstrate that this method allows the metamaterial resonance to be shifted by 31% of the central frequency.
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Journal of The Optical Society of America B-optical Physics, Sep 11, 2019
Metal-based perfect absorbers that use metals such as aluminum (Al) can have their optical proper... more Metal-based perfect absorbers that use metals such as aluminum (Al) can have their optical properties changed with temperature, subsequently affecting the device’s performance. The changes with temperature can critically limit the applications of absorbers at high powers or high temperatures. In this paper, we show a thermally stable broadband absorber based on an ultrathin layer of refractory ceramic, tungsten boride (WB). We experimentally analyze and compare the performance of the absorber with an aluminum (Al) based absorber. The multilayer perfect absorber has absorption higher than 85% in the wavelength range between 500 and 1600 nm over a large range of incident angles (up to 60°). We show that a WB absorber has significantly better temperature stability when compared with its Al counterpart, achieving stable operation up to temperatures as high as 270°C. These absorbers may find applications in solar thermo-photovoltaic energy conversion.
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Scientific Reports, Nov 4, 2019
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2017 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), 2017
This paper proposes a new and flexible approach to control the electric field enhancement of bow-... more This paper proposes a new and flexible approach to control the electric field enhancement of bow-tie nano-antennas by integrating them on the lateral of a ∼ 9 μm tapered optical fiber. The device may find applications in bio-sensing and imaging.
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2016 IEEE Photonics Conference (IPC), 2016
We analyze a multi-layered nano-antenna made of alternating layers of silica and gold. We show th... more We analyze a multi-layered nano-antenna made of alternating layers of silica and gold. We show that a multi-layered structure can produce higher (two times) electric field enhancement than a pure gold antenna.
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2016 IEEE Photonics Conference (IPC), 2016
We propose and analyze a nanoscale plasmonic structure that can work as an optical mode controlle... more We propose and analyze a nanoscale plasmonic structure that can work as an optical mode controller and electro-absorption (EA) modulator at 1550 nm.
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Journal of Physics: Conference Series, 2022
Due to the large binding energy and direct bandgap, transition-metal dichalcogenides (TMDCs) mono... more Due to the large binding energy and direct bandgap, transition-metal dichalcogenides (TMDCs) monolayers have been considered a perfect platform for realising strong coupling at room temperature. It is well established that the quality factor (Q-factor) plays a crucial role in enhancing strong coupling. In this work, we demonstrate the improved strong coupling between the exciton of the WSe2 monolayer and the high Q cavity resonance based on symmetry protected magnetic dipole (MD) bound state in the continuum (BIC). We have found that the Rabi-splitting of the strongly coupled system could be largely enhanced by adjusting the location of the TMDC monolayer, increasing the Q-factor, and reducing the grating thickness. After carefully adjusting the three critical parameters, a Rabi-splitting as high as 38 meV was achieved limited by the oscillator strength of the WSe2 monolayer. Our system could be considered an excellent platform to realise ultra-thin polaritonic devices.
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A continuous 2π phase modulation is crucial for efficient wavefront control. We propose a metasur... more A continuous 2π phase modulation is crucial for efficient wavefront control. We propose a metasurface based on graphene resonators which can cover the complete 2π phase region. A mirror capable of focusing multiple wavelengths in terahertz range is designed and studied.
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Proceedings of SPIE, Aug 28, 2008
ABSTRACT
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A nanolaser using AlGaAs nanodisk is theoretically demonstrated based on anapole state. The radiu... more A nanolaser using AlGaAs nanodisk is theoretically demonstrated based on anapole state. The radius and height of the nanodisk are optimized to be 240nm and 120nm through geometry tuning based on Mie scattering theory. We have achieved near-field lasing at 1017nm with linewidth around 3.5nm.
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Physica Status Solidi (rrl), Jul 21, 2010
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Proceedings of SPIE, Sep 15, 2004
Photonic devices based on 2D PCs have so far been principally targeted at operation in a wave-gui... more Photonic devices based on 2D PCs have so far been principally targeted at operation in a wave-guided configuration and at providing the basic building blocks for Photonic Integration. The problem of optical losses, which are considered as hindering the ...
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IEEE Photonics Journal, Jun 1, 2019
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Optics Communications, 2001
This article describes the analytic behavior of an asymmetric triple mode evolution coupler. This... more This article describes the analytic behavior of an asymmetric triple mode evolution coupler. This new design, based on window filter functions, is analyzed by the coupled mode theory, and its performance verified by the method of lines. The validity of the formulation based on mode coupling is determined, where fabrication tolerances are assessed and checked for several design parameters. Wavelength
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Papers by Haroldo Hattori