scholarly journals Design of Transparent Metasurfaces Based on Asymmetric Nanostructures for Directional and Selective Absorption

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3751
Author(s):  
Dong Wu ◽  
Yang Meng ◽  
Chang Liu
Keyword(s):  
Solar Radiation ◽  
Energy Saving ◽  
Noble Metals ◽  
Near Infrared ◽  
Low Cost ◽  
Infrared Light ◽  
Manufacturing Cost ◽  
Selective Absorption ◽  
Metal Insulator Metal ◽  
Peak Value

Maximizing the solar heat gain through windows in winter and minimizing the solar radiation entering the room in summer are of great significance for the energy saving of buildings. Here, we present a new idea for transparent metasurfaces, based on asymmetric metal/insulator/metal (MIM) nanostructures, which can be switched back and forth between absorbing and reflecting solar radiation by reversing the sample orientation. Owing to the fundamental mode of a low-quality-factor resonance, a selective near-infrared absorption is obtained with an absorption peak value of 90% upon front illumination. The average solar absorption (45%) is about 10% higher than that (35%) of reported transparent absorbers. The near-infrared light is also strongly and selectively reflected upon back illumination and a reflection peak value above 70% is observed. Meanwhile, the average visible transmission of the metasurface is above 60%, which is about 1.6 times that (36%) of previous transparent metasurface absorbers. In addition, Cu material can replace the noble metals in this work, which will greatly reduce the manufacturing cost. Owing to the attractive properties of directional and selective absorption, passive operation mode, and low cost of the materials, the metasurfaces have promising prospects in building energy saving or other solar applications where surface transparency is desirable.

The energy separation effect based on the disk resonance multichannel MIM waveguide

2016 ◽  
Vol 30 (28) ◽  
pp. 1650344
Author(s):  
Liu Wang ◽  
Ya-Ping Zeng ◽  
Zhi-Yong Wang ◽  
Xiong-Ping Xia ◽  
Qiu-Qun Liang
Keyword(s):  
Near Infrared ◽  
Fdtd Method ◽  
Output Port ◽  
Infrared Light ◽  
Energy Separation ◽  
Band Pass Filter ◽  
Separation Function ◽  
Pass Filter ◽  
Metal Insulator Metal ◽  
Mim Waveguide

In this paper, a multichannel metal–insulator–metal (MIM) waveguide structure based on a disk resonator is proposed. The transmission characteristics of visible and near-infrared light in the waveguide are investigated by using the finite-difference time-domain (FDTD) method. The results show that the structure has typical band-pass filter function due to the wave resonance in the nanodisk. The energy of the second-order resonance wavelength of the disk can transmit through each output port averagely, which is realized by the energy separation function of the electromagnetic wave. Moreover, the wavelength will transmit through the output port in redshift as the radius and/or the refractive index of the disk are increased. The transmissivity is sharply reduced with the increase of the coupling thickness between the disk and the output port waveguide.

Influence of Sputtering Power on the Structure, Optical and Electric Properties of Cu3N Films

2015 ◽  
Vol 814 ◽  
pp. 596-600 ◽  
Author(s):  
Li Na Chen ◽  
Jin Feng Leng ◽  
Zhong Xi Yang ◽  
Zhi Chao Meng ◽  
Bin Sun
Keyword(s):  
Near Infrared ◽  
Optical Band Gap ◽  
Infrared Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sputtering Power ◽  
Deposition Power ◽  
Higher Power ◽  
Uv Visible ◽  
Peak Value

The Cu3N films were deposited successfully by reactive direct current magnetron sputtering, the films were comprehensively and systematically characterized by X-ray diffraction analyzer (XRD), UV-Visible spectrophotometer, four-probe resistance tester and other instruments. Results showed that under low deposition power (80W~100W), crystal orientation increased, which is attributed to higher energy under higher power. When sputtering power exceeded the value, excessive energy led to anti-sputtering hindering the process of further nucleation and growth of films. The transmittance of the films deposited under 100W reached the peak value of 78% on the scope of near-infrared light, and optical band gap (Eg) of 1.35ev. The resistivity of Cu3N films increased from 9.68×102Ω.cm to 2.12×103Ω.cm with increasing in sputtering power up to 100W.

scholarly journals Solution-processed near-infrared Cu(In,Ga)(S,Se)2 photodetectors with enhanced chalcopyrite crystallization and bandgap grading structure via potassium incorporation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joo-Hyun Kim ◽  
Hyemi Han ◽  
Min Kyu Kim ◽  
Jongtae Ahn ◽  
Do Kyung Hwang ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Grain Growth ◽  
Carrier Mobility ◽  
Near Infrared ◽  
Low Cost ◽  
Charge Carrier Mobility ◽  
Infrared Region ◽  
Infrared Light ◽  
Large Area ◽  
Solution Processed

AbstractAlthough solution-processed Cu(In,Ga)(S,Se)2 (CIGS) absorber layers can potentially enable the low-cost and large-area production of highly stable electronic devices, they have rarely been applied in photodetector applications. In this work, we present a near-infrared photodetector functioning at 980 nm based on solution-processed CIGS with a potassium-induced bandgap grading structure and chalcopyrite grain growth. The incorporation of potassium in the CIGS film promotes Se uptake in the bulk of the film during the chalcogenization process, resulting in a bandgap grading structure with a wide space charge region that allows improved light absorption in the near-infrared region and charge carrier separation. Also, increasing the Se penetration in the potassium-incorporated CIGS film leads to the enhancement of chalcopyrite crystalline grain growth, increasing charge carrier mobility. Under the reverse bias condition, associated with hole tunneling from the ZnO interlayer, the increasing carrier mobility of potassium-incorporated CIGS photodetector improved photosensitivity and particularly external quantum efficiency more than 100% at low light intensity. The responsivity and detectivity of the potassium-incorporated CIGS photodetector reach 1.87 A W−1 and 6.45 $$\times$$ ×  1010 Jones, respectively, and the − 3 dB bandwidth of the device extends to 10.5 kHz under 980 nm near-infrared light.

scholarly journals Enhanced Antibacterial Activity of CuS-BSA/Lysozyme under Near Infrared Light Irradiation

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2156
Author(s):  
Abir Swaidan ◽  
Sena Ghayyem ◽  
Alexandre Barras ◽  
Ahmed Addad ◽  
Sabine Szunerits ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Near Infrared ◽  
Low Cost ◽  
Drug Carrier ◽  
Effective Means ◽  
Infrared Light ◽  
Antibacterial Drug ◽  
Bacterial Killing ◽  
X Ray

The synthesis of multifunctional photothermal nanoagents for antibiotic loading and release remains a challenging task in nanomedicine. Herein, we investigated a simple, low-cost strategy for the preparation of CuS-BSA nanoparticles (NPs) loaded with a natural enzyme, lysozyme, as an antibacterial drug model under physiological conditions. The successful development of CuS-BSA NPs was confirmed by various characterization tools such as transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Lysozyme loading onto CuS-BSA NPs was evaluated by UV/vis absorption spectroscopy, Fourier-transform infrared spectroscopy (FTIR), zeta potential, and dynamic light scattering measurements. The CuS-BSA/lysozyme nanocomposite was investigated as an effective means for bacterial elimination of B. subtilis (Gram-positive) and E. coli (Gram-negative), owing to the combined photothermal heating performance of CuS-BSA and lysozyme release under 980 nm (0.7 W cm−2) illumination, which enhances the antibiotic action of the enzyme. Besides the photothermal properties, CuS-BSA/lysozyme nanocomposite possesses photodynamic activity induced by NIR illumination, which further improves its bacterial killing efficiency. The biocompatibility of CuS-BSA and CuS-BSA/Lysozyme was elicited in vitro on HeLa and U-87 MG cancer cell lines, and immortalized human hepatocyte (IHH) cell line. Considering these advantages, CuS-BSA NPs can be used as a suitable drug carrier and hold promise to overcome the limitations of traditional antibiotic therapy.

scholarly journals Paper-Based Low Cost Optical Filter

2020 ◽  
Author(s):  
Ajay Tripathi ◽  
Rajesh Rawat ◽  
Archana Tiwari
Keyword(s):  
White Light ◽  
Near Infrared ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Optical Filter ◽  
Infrared Region ◽  
White Paper ◽  
Selective Absorption ◽  
Absorption Mechanism ◽  
Light Emitting

<p>We report simple and inexpensive technique using several sheets of white paper for filtering the blue and non-blue radiation of a white light emitting diode source in the transmission mode. We visibly illustrate successful rejection of specific energy of white light by the filtering papers through absorption mechanism where weak transmission of blue and red radiations are observed. In addition, photoluminescence arising from the papers in near infrared region is also presented while using the white light excitation. Owing to the presence of different whitening agents in the papers, selective absorption and divergent coloured emission from the sheets are observed.</p>

scholarly journals Functional interferometric diffusing wave spectroscopy of the human brain

2021 ◽  
Vol 7 (20) ◽  
pp. eabe0150
Author(s):  
Wenjun Zhou ◽  
Oybek Kholiqov ◽  
Jun Zhu ◽  
Mingjun Zhao ◽  
Lara L. Zimmermann ◽  
...  
Keyword(s):  
Blood Flow ◽  
Near Infrared ◽  
Continuous Wave ◽  
Brain Activity ◽  
Low Cost ◽  
Infrared Light ◽  
Flow Index ◽  
Diffusing Wave Spectroscopy ◽  
Detector Arrays ◽  
Blood Flow Index

Cerebral blood flow (CBF) is essential for brain function, and CBF-related signals can inform us about brain activity. Yet currently, high-end medical instrumentation is needed to perform a CBF measurement in adult humans. Here, we describe functional interferometric diffusing wave spectroscopy (fiDWS), which introduces and collects near-infrared light via the scalp, using inexpensive detector arrays to rapidly monitor coherent light fluctuations that encode brain blood flow index (BFI), a surrogate for CBF. Compared to other functional optical approaches, fiDWS measures BFI faster and deeper while also providing continuous wave absorption signals. Achieving clear pulsatile BFI waveforms at source-collector separations of 3.5 cm, we confirm that optical BFI, not absorption, shows a graded hypercapnic response consistent with human cerebrovascular physiology, and that BFI has a better contrast-to-noise ratio than absorption during brain activation. By providing high-throughput measurements of optical BFI at low cost, fiDWS will expand access to CBF.

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