scholarly journals Lattice Rayleigh Anomaly Associated Enhancement of NH and CH Stretching Modes on Gold Metasurfaces for Overtone Detection

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1265 ◽  
Author(s):  
Daler R. Dadadzhanov ◽  
Tigran A. Vartanyan ◽  
Alina Karabchevsky
Keyword(s):  
Near Infrared ◽  
Field Enhancement ◽  
Dielectric Substrate ◽  
Square Lattice ◽  
Localized Surface Plasmon ◽  
Absorption Enhancement ◽  
Absorption Bands ◽  
Transparent Dielectric ◽  
Infrared Spectral ◽  
Rayleigh Anomaly

Molecular overtones stretching modes that occupy the near-infrared (NIR) are weak compared to the fundamental vibrations. Here we report on the enhancement of absorption by molecular vibrations overtones via electromagnetic field enhancement of plasmonic nanoparallelepipeds comprising a square lattice. We explore numerically, using finite element method (FEM), gold metasurfaces on a transparent dielectric substrate covered by weakly absorbing analyte supporting N-H and C-H overtone absorption bands around 1.5 μ m and around 1.67 μ m, respectively. We found that the absorption enhancement in N-H overtone transition can be increased up to the factor of 22.5 due to the combination of localized surface plasmon resonance in prolonged nanoparticles and lattice Rayleigh anomaly. Our approach may be extended for sensitive identification of other functional group overtone transitions in the near-infrared spectral range.

scholarly journals Effects of Ag Nanocubes with Different Corner Shape on the Absorption Enhancement in Organic Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Feng Shan ◽  
Tong Zhang ◽  
Sheng-Qing Zhu
Keyword(s):  
Solar Cells ◽  
Active Layer ◽  
Organic Solar Cells ◽  
Field Enhancement ◽  
Localized Surface Plasmon ◽  
Absorption Enhancement ◽  
Absorption Performance ◽  
Different Shapes ◽  
Ag Ncs ◽  
Metallic Region

The effects of corner shape of silver (Ag) nanocubes (NCs) on optical absorptions of organic solar cells (OSCs) are theoretically investigated by finite element method (FEM) calculations. The absorption of sun light in the active layer is calculated. Significant absorption enhancements have been demonstrated in metallic region with different shapes of Ag NCs, among them corner radius (R) is zero result in the best light absorption performance of up to 55% enhancement with respect to bare OSCs. The origins of increased absorption are believed to be the effects of the huge electric field enhancement and increased scattering upon the excitation of localized surface plasmon resonance (LSPR). Apart from usingR=0, we show thatR=3, 6, and 11.29 of Ag NCs in metallic region of active layer may also result in the maximum comparable absorption enhancement of 49%, 41%, and 28%, respectively. In addition, a significant effect of the period of NCs is observed.

Tunable localized surface plasmon resonances of asymmetric Au/SiO2/Au cross-shape nanobars

2014 ◽  
Vol 28 (17) ◽  
pp. 1450143 ◽  
Author(s):  
M. L. Wan ◽  
H. J. Du ◽  
Y. L. Song ◽  
F. Q. Zhou ◽  
K. J. Dai
Keyword(s):  
Electric Fields ◽  
Surface Plasmon ◽  
Near Infrared ◽  
Dipole Approximation ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonances ◽  
Localized Surface Plasmon Resonances ◽  
Plasmon Resonances ◽  
Surface Enhanced Raman ◽  
Infrared Spectral

The plasmonic properties of asymmetric Au / SiO 2/ Au sandwiched cross-shape nanobars are investigated theoretically using the discrete dipole approximation (DDA) method. Two localized surface plasmon resonances are observed in the extinction spectra, which perform extreme sensitivity to the length and width of the nanobar and can be tuned easily throughout visible and into near-infrared spectral regions. The local electric fields around the nanobar are calculated and a pure electromagnetic Raman enhancement factor of about 106 can be achieved. In addition, compared to a monolayer gold nanobar, it exhibits more "hot spots" and stronger localized electric field enhancements. This plasmonic substrate provides potential applications in surface enhanced Raman scattering (SERS) and nonlinear optical devices.

scholarly journals Plasmon-Enhanced Photoresponse of Self-Powered Si Nanoholes Photodetector by Metal Nanowires

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2460
Author(s):  
Pericle Varasteanu ◽  
Antonio Radoi ◽  
Oana Tutunaru ◽  
Anton Ficai ◽  
Razvan Pascu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Simulation Analysis ◽  
Field Enhancement ◽  
Metal Nanowires ◽  
Local Surface Plasmon Resonance ◽  
Resonance Effects ◽  
Enhanced Sensitivity ◽  
Infrared Spectral ◽  
Self Powered ◽  
Cost Efficient

In this work, we report the development of self-powered photodetectors that integrate silicon nanoholes (SiNHs) and four different types of metal nanowires (AgNWs, AuNWs, NiNWs, PtNWs) applied on the SiNHs’ surface using the solution processing method. The effectiveness of the proposed architectures is evidenced through extensive experimental and simulation analysis. The AgNWs/SiNHs device showed the highest photo-to-dark current ratio of 2.1 × 10−4, responsivity of 30 mA/W and detectivity of 2 × 1011 Jones along with the lowest noise equivalent power (NEP) parameter of 2.4 × 10−12 WHz−1/2 in the blue light region. Compared to the bare SiNHs device, the AuNWs/SiNHs device had significantly enhanced responsivity up to 15 mA/W, especially in the red and near-infrared spectral region. Intensity-modulated photovoltage spectroscopy (IMVS) measurements revealed that the AgNWs/SiNHs device generated the longest charge carrier lifetime at 470 nm, whereas the AuNWs/SiNHs showed the slowest recombination rate at 627 nm. Furthermore, numerical simulation confirmed the local field enhancement effects at the MeNWs and SiNHs interface. The study demonstrates a cost-efficient and scalable strategy to combine the superior light harvesting properties of SiNHs with the plasmonic absorption of metallic nanowires (MeNWs) towards enhanced sensitivity and spectral-selective photodetection induced by the local surface plasmon resonance effects.

scholarly journals Ultrabroadband Absorption Enhancement via Hybridization of Localized and Propagating Surface Plasmons

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1625
Author(s):  
Tian Sang ◽  
Honglong Qi ◽  
Xun Wang ◽  
Xin Yin ◽  
Guoqing Li ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Near Infrared ◽  
Low Cost ◽  
Polarized Light ◽  
Wavelength Region ◽  
Transverse Magnetic ◽  
Localized Surface Plasmon ◽  
Absorption Enhancement ◽  
Geometrical Parameters ◽  
Light Illumination

Broadband metamaterial absorbers (MAs) are critical for applications of photonic and optoelectronic devices. Despite long-standing efforts on broadband MAs, it has been challenging to achieve ultrabroadband absorption with high absorptivity and omnidirectional characteristics within a comparatively simple and low-cost architecture. Here we design, fabricate, and characterize a novel compact Cr-based MA to achieve ultrabroadband absorption in the visible to near-infrared wavelength region. The Cr-based MA consists of Cr nanorods and Cr substrate sandwiched by three pairs of SiO2/Cr stacks. Both simulated and experimental results show that an average absorption over 93.7% can be achieved in the range of 400–1000 nm. Specifically, the ultrabroadband features result from the co-excitations of localized surface plasmon (LSP) and propagating surface plasmon (PSP) and their synergistic absorption effects, where absorption in the shorter and longer wavelengths are mainly contributed bythe LSP and PSP modes, respectively. The Cr-based MA is very robust to variations of the geometrical parameters, and angle-and polarization-insensitive absorption can be operated well over a large range of anglesunder both transverse magnetic(TM)- and transverse electric (TE)-polarized light illumination.

scholarly journals Computational and Experimental Analysis of Gold Nanorods in Terms of Their Morphology: Spectral Absorption and Local Field Enhancement

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1696
Author(s):  
Juan Manuel Núñez-Leyva ◽  
Eleazar Samuel Kolosovas-Machuca ◽  
John Sánchez ◽  
Edgar Guevara ◽  
Alexander Cuadrado ◽  
...  
Keyword(s):  
Optical Properties ◽  
Numerical Simulations ◽  
Gold Nanorods ◽  
Local Field ◽  
Strong Dependence ◽  
Field Enhancement ◽  
Dielectric Substrate ◽  
Spectral Absorption ◽  
Absorption Bands ◽  
Local Field Enhancement

A nanoparticle’s shape and size determine its optical properties. Nanorods are nanoparticles that have double absorption bands associated to surface plasmon oscillations along their two main axes. In this work, we analize the optical response of gold nanorods with numerical simulations and spectral absorption measurements to evaluate their local field enhancement—which is key for surface-enhanced Raman spectroscopic (SERS) applications. Our experimental results are in good agreement with finite element method (FEM) simulations for the spectral optical absorption of the nanoparticles. We also observed a strong dependence of the optical properties of gold nanorods on their geometrical dimension and shape. Our numerical simulations helped us reveal the importance of the nanorods’ morphology generated during the synthesis stage in the evaluation of absorption and local field enhancement. The application of these gold nanorods in surface-enhancement Raman spectroscopy is analyzed numerically, and results in a 5.8×104 amplification factor when comparing the values obtained for the nanorod deposited on a dielectric substrate compared to the nanorod immersed in water.

Wavelength-Selective Solar Thermal Absorber With Two-Dimensional Nickel Gratings

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Bong Jae Lee ◽  
Yu-Bin Chen ◽  
Sunwoo Han ◽  
Feng-Cheng Chiu ◽  
Hyun Jin Lee
Keyword(s):  
Solar Radiation ◽  
Near Infrared ◽  
Broad Band ◽  
Sio2 Film ◽  
Solar Thermal ◽  
Local Magnetic Field ◽  
Absorption Enhancement ◽  
Two Dimensional ◽  
Nickel Substrate ◽  
Infrared Spectral

The direct utilization of solar radiation has been considered a promising energy source because of its abundance, sustainability, and cleanness. The conversion of solar radiation into usable heat largely depends on the absorption characteristics of a solar thermal collector. In the present study, we conducted design analysis of a wavelength-selective absorber composed of a two-dimensional Nickel grating, a thin SiO2 film, and a Nickel substrate. Dimensions of the two-dimensional grating were determined with the Taguchi method, which optimized the spectral absorptance for both polarizations. The spectral absorptance demonstrated a broad-band plateau within the visible and the near-infrared spectral region, but it was significantly suppressed at longer wavelengths. Moreover, the absorptance plateau was nearly insensitive to the incident orientation of solar radiation. Physical mechanisms of the absorption enhancement were elucidated with the local magnetic field distribution.

scholarly journals Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3247
Author(s):  
Lina Grineviciute ◽  
Soon Hock Ng ◽  
Molong Han ◽  
Tania Moein ◽  
Vijayakumar Anand ◽  
...  
Keyword(s):  
Angular Dependence ◽  
Field Enhancement ◽  
Absorption Bands ◽  
Mid Infrared ◽  
Infrared Microspectroscopy ◽  
Enhanced Absorption ◽  
Glancing Angle ◽  
Infrared Spectral ◽  
Stretching Vibration ◽  
Polarisation Analysis

Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1 μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70∘ to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared Microspectroscopy (IRM) beamline at Australian Synchrotron. Specific absorption bands, particularly Si-O-Si stretching vibration, was found to follow the angular dependence of ∼cos2θ, consistent with the absorption anisotropy. This unexpected anisotropy stems from the enhanced absorption in nano-crevices, which have orientation following the cos2θ angular dependence as revealed by Fourier transforming the image of the surface of 3D columnar films and numerical modeling of light field enhancement by sub-wavelength nano-crevices.

A fiber-optic sensor for neurotransmitters with ultralow concentration: near-infrared plasmonic electromagnetic field enhancement using raspberry-like meso-SiO2 nanospheres

Nanoscale ◽  
2017 ◽  
Vol 9 (39) ◽  
pp. 14929-14936 ◽  
Author(s):  
Yunyun Huang ◽  
Mingfei Ding ◽  
Tuan Guo ◽  
Dejiao Hu ◽  
Yaoyu Cao ◽  
...  
Keyword(s):  
Localized Surface Plasmon Resonance ◽  
Near Infrared ◽  
Fiber Optic ◽  
Field Enhancement ◽  
Fiber Optic Sensor ◽  
Localized Surface Plasmon ◽  
Optic Sensor ◽  
Ultralow Concentration ◽  
Resonance Enhancement ◽  
Infrared Wavelengths

A localized surface plasmon resonance enhancement at near infrared wavelengths has been achieved by constructing raspberry-like meso-SiO2 nanospheres.

scholarly journals Wideband Absorption at Low Microwave Frequencies Assisted by Magnetic Squeezing in Metamaterials

2020 ◽  
Vol 8 ◽  
Author(s):  
Zhenxu Wang ◽  
Jiafu Wang ◽  
Yajuan Han ◽  
Ya Fan ◽  
Xinmin Fu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Compatibility ◽  
High Efficiency ◽  
Field Enhancement ◽  
Normal Incidence ◽  
Resonance Region ◽  
Square Lattice ◽  
Absorption Enhancement ◽  
Squeezing Effect ◽  
Low Frequencies

In this paper, the magnetic squeezing effect in metamaterials is explored and applied to achieve wideband absorption in low-frequency microwave bands. To this end, a metamaterial absorber (MA) is proposed, which consists of a square lattice of a split ring resonator (SRR) placed on top of a magnetic absorbing material (MAM) layer backed by a conducting ground. In the positive resonance region of SRRs, a strong magnetic squeezing effect occurs and more concentrated magnetic field lines are confined within SRRs. This results in significant magnetic field enhancement within the MAM layer, which provides a prerequisite for high-efficiency absorption enhancement at low frequencies. To verify this method, we fabricated a prototype using a 3.0 mm thick silicone MAM sheet. Both the simulation and experiment results show that with the assistance of magnetic squeezing in the SRR array, the absorption at lower frequencies is significantly enhanced and is above 90% in 1.25–2.31 GHz under normal incidence. Furthermore, the MA exhibits satisfactory stability for different polarization states and incident angles due to the square lattice of the SRR array. This design method may find potential applications in fields such as electromagnetic compatibility, wireless communication, and others.

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