scholarly journals Tunable Faraday rotation of ferromagnet thin film in whole visible region coupled with aluminum plasmonic arrays

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Feifei Zhang ◽  
Taisuke Atsumi ◽  
Xiaolun Xu ◽  
Shunsuke Murai ◽  
Katsuhisa Tanaka
Keyword(s):  
Faraday Rotation ◽  
Noble Metals ◽  
Spectral Response ◽  
Visible Region ◽  
Visible Spectrum ◽  
Ferromagnetic Film ◽  
Visible Range ◽  
Plasmonic Nanostructures ◽  
Blue Range ◽  
Dielectric Environment

Abstract To date, the plasmonic nanostructure utilized for magneto-optical (MO) enhancement has been limited to noble metals with resulted enhancement in the green-red part of visible spectrum. In this study, we fabricated a diffractive hexagonal array composed of Al nanoparticles (NPs) with a thin 7.5 nm ferromagnetic film and pushed the enhanced Faraday rotation (FR) into the blue to green range of the visible light. The freedom and ability to control the working spectral region in the whole visible range from 400 to 800 nm were also demonstrated by changing the lattice constant and the dielectric environment of plasmonic nanostructures. Particularly, in the blue range we obtained the maximum FR 0.57° at 410 nm with a broad boosting region around 0.5° from 400 to 500 nm. Moreover, the largest FR 1.66° was shown at 638 nm by tuning the dielectric environment into a higher refractive index medium. The results of our investigation demonstrate the potential of Al-based magnetoplasmonic effect and offer opportunities to push the MO spectral response out of visible range into the ultraviolet-blue range.

scholarly journals DIGITAL IMAGE ANALYSIS OF THE VISIBLE REGION THROUGH SIMULATION OF ROCK ART PAINTINGS

2016 ◽  
Author(s):  
Berta Carrión-Ruiz ◽  
Silvia Blanco-Pons ◽  
Jose Luis Lerma
Keyword(s):  
Rock Art ◽  
Visible Region ◽  
Visible Spectrum ◽  
Principal Component ◽  
Optical Filters ◽  
Visible Range ◽  
Redundant Data ◽  
The Difference ◽  
Entire Visible Spectrum ◽  
New Research

Non-destructive rock art recording techniques are getting special attention in the last years, opening new research lines in order to improve the level of documentation and understanding of our rich legacy. This paper applies the principal component analysis (PCA) technique in images that include wavelengths between 400-700 nm (visible  range). Our approach is focused on determining the difference provided by the image processing of the visible region through four spectral images versus an image that encompasses the entire visible spectrum. The images were taken by means of optical filters that take specific wavelengths and exclude parts of the spectrum. Simulation of rock art is prepared in laboratory. For this purpose, three different pigments were made simulating the material composition of rock art paintings. The advantages of studying the visible spectrum in separate images are analysed. In addition, PCA is applied to each of the images to reduce redundant data. Finally, PCA is applied to the image that contains the entire visible spectrum and is compared with previous results. Through the results of the four visible spectral images one can begin to draw conclusions about constituent painting materials without using decorrelation techniques.

Novel device for implementation of WDM in the visible spectrum

2012 ◽  
Vol 1438 ◽  
Author(s):  
P. Louro ◽  
M. Vieira ◽  
M. A. Vieira ◽  
V. Silva ◽  
A. Fantoni
Keyword(s):  
Steady State ◽  
Spectral Response ◽  
Visible Spectrum ◽  
Visible Range ◽  
Light Conditions ◽  
Optical Signals ◽  
Novel Device ◽  
Insight Into ◽  
Selective Behavior

ABSTRACTIn this paper we report the use of a device based on two multilayered a-SiC:H/a-Si:H stacked heterostructures to photodetect and demultiplex optical signals of the visible spectrum. Both heterostructures were optimized for the detection of short and long wavelengths within the visible range. The optoelectronic characterization of the device includes spectral response measurements under reverse bias and using different optical steady state light conditions to soak the device. Results show that the device photocurrent signal measured using appropriate steady state optical bias, allows the separate detection of the input transmitted signals which enables the demultiplexing task. A numerical simulation, gives insight into the transduction mechanism to explain the device wavelength selective behavior.

Photo- and thermo-activated electron transfer system based on a luminescent europium organic framework with spectral response from UV to visible range

2014 ◽  
Vol 50 (88) ◽  
pp. 13544-13546 ◽  
Author(s):  
Hengjun Chen ◽  
Guiming Zheng ◽  
Min Li ◽  
Yifang Wang ◽  
Yang Song ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Methyl Viologen ◽  
Spectral Response ◽  
Visible Region ◽  
Visible Range ◽  
Transfer System ◽  
Stimuli Responsive ◽  
Electron Transfer System ◽  
Organic Framework

A dual stimuli-responsive system with spectral response from UV to the visible region was constructed by introducing methyl viologen into a luminescent Eu-MOF with a compact packing mode.

scholarly journals Pandemic of Childhood Myopia. Could New Indoor LED Lighting Be Part of the Solution?

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3827
Author(s):  
David Baeza Moyano ◽  
Roberto Alonso González-Lezcano
Keyword(s):  
Technological Progress ◽  
Visible Spectrum ◽  
Visible Range ◽  
Natural Light ◽  
Genetic Origin ◽  
Led Lighting ◽  
Health Authorities ◽  
The World ◽  
Children’S Work ◽  
Possible Cause

The existence of a growing myopia pandemic is an unquestionable fact for health authorities around the world. Different possible causes have been put forward over the years, such as a possible genetic origin, the current excess of children’s close-up work compared to previous stages in history, insufficient natural light, or a multifactorial cause. Scientists are looking for different possible solutions to alleviate it, such as a reduction of time or a greater distance for children’s work, the use of drugs, optometric correction methods, surgical procedures, and spending more time outdoors. There is a growing number of articles suggesting insufficient natural light as a possible cause of the increasing levels of childhood myopia around the globe. Technological progress in the world of lighting is making it possible to have more monochromatic LED emission peaks, and because of this, it is possible to create spectral distributions of visible light that increasingly resemble natural light in the visible range. The possibility of creating indoor luminaires that emit throughout the visible spectrum from purple to infrared can now be a reality that could offer a new avenue of research to fight this pandemic.

scholarly journals Preparation of ZnO-Zn2TiO4Sol Composite Films and Its Photocatalytic Activities

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xiujuan Qin ◽  
Li Cui ◽  
Guangjie Shao
Keyword(s):  
Methyl Orange ◽  
Photocatalytic Oxidation ◽  
Spectral Response ◽  
Sol Gel ◽  
Composite Films ◽  
Visible Region ◽  
Performance Testing ◽  
Structure Characterization ◽  
Semiconductor Oxides ◽  
Wide Range

Ti-doped ZnO sol-composite films were prepared on the glass substrate by the two-step sol-gel technique. X-ray diffraction, Uv-Vis spectrophotometer, and FS spectrum of composite films were used to help make structure characterization and optical performance testing. The results showed that the composite was a mixture of ZnO + Zn2TiO4. Because of synergistic effect of both semiconductor oxides, composite films had a wide range of spectral response in the visible region, and the absorption band edge was about 510 nm, and the Green Belt of composite films luminous significantly enhanced. Photocatalytic oxidation experiments showed that using the composite films treatment (16.5 ml, l0 mg/L methyl orange aqueous solution)/cm2, the decolorization rate of methyl-orange was 90% after 3 hours irradiation.

Organic photodetector with spectral response tunable across the visible spectrum by means of internal optical microcavity

2009 ◽  
Vol 10 (6) ◽  
pp. 1152-1157 ◽  
Author(s):  
Kwang Hyup An ◽  
Brendan O’Connor ◽  
Kevin P. Pipe ◽  
Max Shtein
Keyword(s):  
Spectral Response ◽  
Visible Spectrum ◽  
Optical Microcavity ◽  
Organic Photodetector

scholarly journals Syntheses of Colloidal F:In2O3 Cubes: Fluorine-Induced Faceting and Infrared Plasmonic Response

2018 ◽  
Author(s):  
Shin Hum Cho ◽  
Sandeep Ghosh ◽  
Zachariah J. Berkson ◽  
Jordan A. Hachtel ◽  
Jianjian Shi ◽  
...  
Keyword(s):  
Density Functional ◽  
Spectral Response ◽  
Visible Region ◽  
Scanning Transmission Electron Microscope ◽  
Colloidal Synthesis ◽  
Localized Surface Plasmon ◽  
High Concentration ◽  
Surface Binding ◽  
Transmission Electron ◽  
Scanning Transmission

Cube-shaped nanocrystals (NCs) of conventional metals like gold and silver generally exhibit localized surface plasmon resonance (LSPR) in the visible region with spectral modes determined by their faceted shapes. However, faceted NCs exhibiting LSPR response in the infrared (IR) region are relatively rare. Here, we describe the colloidal synthesis of nanoscale fluorine-doped indium oxide (F:In<sub>2</sub>O<sub>3</sub>) cubes with LSPR response in the IR region, wherein fluorine was found to both direct the cubic morphology and act as an aliovalent dopant. Single crystalline 160 nm F:In<sub>2</sub>O<sub>3</sub> cubes terminated by (100) facets and concave cubes were synthesized using a colloidal heat-up method. The presence of fluorine was found to impart higher stabilization to the (100) facets through density functional theory (DFT) calculations that evaluated the energetics of F-substitution at surface oxygen sites. These calculations suggest that the cubic morphology results from surface binding of F-atoms. In addition, fluorine acts as an anionic aliovalent dopant in the cubic bixbyite lattice of In<sub>2</sub>O<sub>3</sub>, introducing a high concentration of free electrons leading to LSPR. We confirmed the presence of lattice fluorine dopants in these cubes using solid-state <sup>19</sup>F and <sup>115</sup>In nuclear magnetic resonance (NMR) spectroscopy. The cubes exhibit narrow, shape-dependent multimodal LSPR extinction peaks due to corner- and edge-centered modes. The spatial origin of these different contributions to the spectral response are directly visualized by electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM).

scholarly journals Люминесцентные свойства нестехиометрических кристаллов ниобата лития различного состава и генезиса (обзор)

2022 ◽  
Vol 130 (1) ◽  
pp. 171
Author(s):  
М.В. Смирнов ◽  
Н.В. Сидоров ◽  
М.Н. Палатников
Keyword(s):  
Wave Spectrum ◽  
Visible Region ◽  
Wavelength Region ◽  
Visible Spectrum ◽  
Luminescent Properties ◽  
Short Wave ◽  
Octahedral Cluster ◽  
Short Wavelength Region ◽  
Luminescence Centers ◽  
Near Ir

A brief review of the features of the defect structure and studies of the luminescent properties of nonlinear optical lithium niobate crystals of various compositions and genesis was given. It was established that the electron-hole pair NbNb4+-O- in the oxygen-octahedral cluster NbO6 emitted in the short-wavelength region of the visible spectrum (400-500 nm), while point defects (VLi and NbNb4+-NbLi4+ bipolarons) - in the long-wavelength region (500-620 nm). At the ratio of Li/Nb≈1 the luminescence was extinguished in the visible region of the spectrum due to decreasing the intrinsic luminescence centers. It was shown that the presence of polaron luminescence in the near-IR region (700-1050 nm) was due to the small polarons NbLi4+ and impurity ions Cr3+ localized in lithium and niobium octahedra. The energy transfer between the luminescence centers in the visible and near-IR spectral regions was detected. Moreover, luminescence in near-IR regions was dominant. Doping of LiNbO3 crystals with zinc and magnesium at ZnO<4.46 mol.% and MgO<5.29 mol.% led to decreasing luminescence of intrinsic defects (VLi, NbNb4+-NbLi4+). However, there was an increase of the contribution of the short-wave spectrum component at higher dopant concentrations because of the introduction of Zn and Mg into the origin positions of Nb ions.

scholarly journals Ultrabroadband two-dimensional electronic spectroscopy reveals energy flow pathways in LHCII across the visible spectrum

2019 ◽  
Vol 205 ◽  
pp. 09034
Author(s):  
Minjung Son ◽  
Alberta Pinnola ◽  
Roberto Bassi ◽  
Gabriela S. Schlau-Cohen
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Energy Flow ◽  
Energy Levels ◽  
Electronic Spectroscopy ◽  
Visible Region ◽  
Visible Spectrum ◽  
Energy Relaxation ◽  
Two Dimensional ◽  
Flow Pathways

We utilise ultrabroadband two-dimensional electronic spectroscopy to map out pathways of energy flow in LHCII across the entire visible region. In addition to the well-established, low-lying chlorophyll Qy bands, our results reveal additional pathways of energy relaxation on the higher-lying excited states involving the S2 energy levels of carotenoids, including ultrafast carotenoid-to-chlorophyll energy transfer on 90-150 fs timescales.

Photoreduction of Dye with Noble Metal Gold Permeated with Metal Oxide Titania

2020 ◽  
Vol 20 (6) ◽  
pp. 3896-3901 ◽  
Author(s):  
Jyoti Bansal ◽  
A. K. Hafiz ◽  
Shailesh Narain Sharma
Keyword(s):  
Metal Oxide ◽  
Noble Metals ◽  
Irradiation Time ◽  
Visible Region ◽  
Visible Absorption ◽  
Photo Degradation ◽  
Sunlight Irradiation ◽  
Tunable Bandgap ◽  
Photo Response ◽  
Uv Visible

Photoactive degradation of textile malachite green (MG), methylene blue (MB) dyes has been permeated on metal oxide TiO2 nanoparticles under sunlight. Semiconductor photocatalysis is a promising method for removal of toxic chemicals from wastewater produced by industry. Due to tunable bandgap, TiO2 among various semiconductor studied mostly. Large band gap (UV active) and recombination of exciton in TiO2 less active in photo degradation. Noble metals such as gold nanoparticles deposited on TiO2 surface increased the optical activity and to shift optical response to visible region. Degradation detail has been carried out by characterisation such as XRD, UV-Vis, PL, TEM, and SEM for MG and MB textile dyes under sunlight irradiation. UV-visible absorption spectra and PL spectra shows that photo-response of as prepared sample is extended from UV to visible region. PL intensity decreases with increases in concentration of Au nanoparticles, decreases in intensity in optical spectra of Au–TiO2 composites shows that charge transfer process dominates. Au–TiO2 plays an essential role in enhancing photocatalytical activity. Decolorization optimization depends on catalyst concentration, Dye concentration, light intensity and, irradiation time.

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