scholarly journals Quadratic Electro-Optic Effect in Metal Nanoparticles in a Transparent Dielectric Medium

2019 ◽  
Vol 9 (2) ◽  
pp. 232 ◽  
Author(s):  
Mrinal Thakur ◽  
Justin Van Cleave
Keyword(s):  
Gold Nanoparticles ◽  
Metal Nanoparticles ◽  
Low Cost ◽  
Dielectric Medium ◽  
Metallic Particles ◽  
Transparent Dielectric ◽  
Electro Optic ◽  
Kerr Coefficient ◽  
New Applications ◽  
First Time

The quadratic electro-optic effect/Kerr coefficients were measured for the first time for metal nanoparticles. In particular, gold nanoparticles in glass were studied. Measurements were made using the field-induced birefringence method at a wavelength near the onset of the surface plasmon resonance. The magnitudes of the Kerr coefficients for different sizes of gold nanoparticles in glass were measured and compared with that of subnanometer size metallic particles in non-conjugated conductive polymers. The magnitude of the Kerr coefficient was found to increase rapidly (about d−3) when the diameter, d, of the nanoparticles was decreased. This is consistent with the existing theories and understanding of nonlinear optics in metal nanoparticles. The results imply a broad range of new applications of metal nanoparticles in electro-optic switching/modulation, low-cost Kerr cells and other uses in optoelectronics.

scholarly journals Electroabsorption in Metallic Nanoparticles within Transparent Dielectric Media

2020 ◽  
Vol 10 (14) ◽  
pp. 4904
Author(s):  
Mrinal Thakur ◽  
Justin Van Cleave
Keyword(s):  
Gold Nanoparticles ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Metallic Nanoparticles ◽  
Conductive Polymer ◽  
Dielectric Media ◽  
Transparent Dielectric ◽  
Electro Optic ◽  
Kerr Coefficient ◽  
Ac Fields

Electroabsorption in metallic nanoparticles within transparent dielectric media has been measured. In particular, gold nanoparticles in glass and subnanometer-size metallic domains in iodine doped nonconjugated conductive polymer have been studied. Measurements have been made for applied ac fields at 4 kHz, at a wavelength close to the onset of the surface plasmon resonance. The measured electroabsorption (imaginary part of χ(3) or Kerr coefficient) has a quadratic dependence on electric field. Its magnitudes were compared for different sizes of the metallic nanoparticles down to the subnanometer-size particles in iodine-doped nonconjugated conductive polymer. As in the case of quadratic electro-optic effect reported earlier, electroabsorption has approximately a 1/d3 dependence, d being the diameter of nanoparticle. This is consistent with existing theories on confined metallic systems.

scholarly journals LiFi Through Reconfigurable Intelligent Surfaces: A New Frontier for 6G?

2021 ◽  
Author(s):  
Hanaa Abumarshoud ◽  
Lina Mohjazi ◽  
Octavia A. Dobre ◽  
Marco Di Renzo ◽  
Muhammad Ali Imran ◽  
...  
Keyword(s):  
Low Cost ◽  
Dynamic Environments ◽  
Line Of Sight ◽  
Visible Light Communications ◽  
Future Directions ◽  
Complex Interactions ◽  
Look Ahead ◽  
New Frontier ◽  
New Applications ◽  
First Time

<div>Light fidelity (LiFi), which is based on visible light communications (VLC), is celebrated as a cutting-edge technological paradigm that is envisioned to be an indispensable part of 6G systems. Nonetheless, LiFi performance is subject to efficiently overcoming the line-of-sight blockage, whose adverse effect on the reliability of wireless reception becomes even more pronounced in highly dynamic environments, such as vehicular applications. Meanwhile, reconfigurable intelligent surfaces (RISs) emerged recently as a revolutionary concept that transforms the physical propagation environment into a fully controllable and customisable space in a low-cost low-power fashion. We anticipate that the integration of RISs in LiFi enabled networks will not only support blockage mitigation but will also provision complex interactions among network entities, and is hence manifested as a promising platform that enables a plethora of technological trends and new applications. In this article, for the first time in the open literature, we set the scene for a holistic overview of RIS-assisted LiFi systems. Specifically, we explore the underlying RIS architecture from the perspective of physics and present a forward-looking vision that outlines potential operational elements supported by RIS-enabled transceivers and RIS-enabled environments. Finally, we highlight major associated challenges and offer a look ahead toward promising future directions.</div>

scholarly journals LiFi Through Reconfigurable Intelligent Surfaces: A New Frontier for 6G?

2021 ◽  
Author(s):  
Hanaa Abumarshoud ◽  
Lina Mohjazi ◽  
Octavia A. Dobre ◽  
Marco Di Renzo ◽  
Muhammad Ali Imran ◽  
...  
Keyword(s):  
Low Cost ◽  
Dynamic Environments ◽  
Line Of Sight ◽  
Visible Light Communications ◽  
Future Directions ◽  
Complex Interactions ◽  
Look Ahead ◽  
New Frontier ◽  
New Applications ◽  
First Time

<div>Light fidelity (LiFi), which is based on visible light communications (VLC), is celebrated as a cutting-edge technological paradigm that is envisioned to be an indispensable part of 6G systems. Nonetheless, LiFi performance is subject to efficiently overcoming the line-of-sight blockage, whose adverse effect on the reliability of wireless reception becomes even more pronounced in highly dynamic environments, such as vehicular applications. Meanwhile, reconfigurable intelligent surfaces (RISs) emerged recently as a revolutionary concept that transforms the physical propagation environment into a fully controllable and customisable space in a low-cost low-power fashion. We anticipate that the integration of RISs in LiFi enabled networks will not only support blockage mitigation but will also provision complex interactions among network entities, and is hence manifested as a promising platform that enables a plethora of technological trends and new applications. In this article, for the first time in the open literature, we set the scene for a holistic overview of RIS-assisted LiFi systems. Specifically, we explore the underlying RIS architecture from the perspective of physics and present a forward-looking vision that outlines potential operational elements supported by RIS-enabled transceivers and RIS-enabled environments. Finally, we highlight major associated challenges and offer a look ahead toward promising future directions.</div>

Synthesis of a silymarin-gold nanoparticle conjugate and analysis of its liver-protecting activity

2021 ◽  
Vol 22 ◽  
Author(s):  
Sergey Staroverov ◽  
Sergey Kozlov ◽  
Alexander Fomin ◽  
Konstantib Gabalov ◽  
Alexey Volkov ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Liver Disease ◽  
Carbon Tetrachloride ◽  
Glutathione Depletion ◽  
Laboratory Animals ◽  
Experimental Hepatitis ◽  
Acute Liver Disease ◽  
The Mean ◽  
Extent Of Damage ◽  
First Time

Background: The liver disease problem prompts investigators to search for new methods of liver treatment. Introduction: Silymarin (Sil) protects the liver by reducing the concentration of free radicals and the extent of damage to the cell membranes. A particularly interesting method to increase the bioavailability of Sil is to use synthesized gold nanoparticles (AuNPs) as reagents. The study considered whether it was possible to use the silymarin-AuNP conjugate as a potential liver-protecting drug. Method: AuNPs were conjugated to Sil and examine the liver-protecting activity of the conjugate. Experimental hepatitis and hepatocyte cytolysis after carbon tetrachloride actionwere used as a model system, and the experiments were conducted on laboratory animals. Result: For the first time, silymarin was conjugated to colloidal gold nanoparticles (AuNPs). Electron microscopy showed that the resultant preparations were monodisperse and that the mean conjugate diameter was 18–30 nm ± 0.5 nm (mean diameter of the native nanoparticles, 15 ± 0.5 nm). In experimental hepatitis in mice, conjugate administration interfered with glutathione depletion in hepatocytes in response to carbon tetrachloride was conducive to an increase in energy metabolism, and stimulated the monocyte–macrophage function of the liver. The results were confirmed by the high respiratory activity of the hepatocytes in cell culture. Conclusion: We conclude that the silymarin-AuNP conjugate holds promise as a liver-protecting agent in acute liver disease caused by carbon tetrachloride poisoning.

High-speed electro-optic switch using buried electrode structure in polymer Mach–Zehnder waveguide

2016 ◽  
Vol 30 (06) ◽  
pp. 1650063 ◽  
Author(s):  
Jingwen Sun ◽  
Jian Sun ◽  
Yunji Yi ◽  
Lucheng Qv ◽  
Shiqi Sun ◽  
...  
Keyword(s):  
Insertion Loss ◽  
Rise Time ◽  
High Speed ◽  
Low Cost ◽  
Characteristic Parameters ◽  
Electrode Structure ◽  
Processing Cost ◽  
Electro Optic ◽  
Disperse Red 1 ◽  
Excellent Photostability

A low-cost and high-speed electro-optic (EO) switch using the guest–host EO material Disperse Red 1/Polymethyl Methacrylate (DR1/PMMA) was designed and fabricated. The DR1/PMMA material presented a low processing cost, an excellent photostability and a large EO coefficient of 13.1 pm/V. To improve the performance of the switch, the in-plane buried electrode structure was introduced in the polymer Mach–Zehnder waveguide to improve the poling and modulating efficiency. The characteristic parameters of the waveguide and the electrodes were carefully designed and the fabrication process was strictly controlled. Under 1550 nm, the insertion loss of the device was 12.7 dB. The measured switching rise time and fall time of the switch were 50.00 ns and 54.29 ns, respectively.

scholarly journals UV Inscription and Pressure Induced Long-Period Gratings through 3D Printed Amplitude Masks

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1977
Author(s):  
Ricardo Oliveira ◽  
Liliana M. Sousa ◽  
Ana M. Rocha ◽  
Rogério Nogueira ◽  
Lúcia Bilro
Keyword(s):  
State Of The Art ◽  
Low Cost ◽  
Resonance Wavelength ◽  
Complex Structures ◽  
Pressing Method ◽  
Long Period ◽  
Long Period Gratings ◽  
3D Printed ◽  
Mechanical Pressing ◽  
First Time

In this work, we demonstrate for the first time the capability to inscribe long-period gratings (LPGs) with UV radiation using simple and low cost amplitude masks fabricated with a consumer grade 3D printer. The spectrum obtained for a grating with 690 µm period and 38 mm length presented good quality, showing sharp resonances (i.e., 3 dB bandwidth < 3 nm), low out-of-band loss (~0.2 dB), and dip losses up to 18 dB. Furthermore, the capability to select the resonance wavelength has been demonstrated using different amplitude mask periods. The customization of the masks makes it possible to fabricate gratings with complex structures. Additionally, the simplicity in 3D printing an amplitude mask solves the problem of the lack of amplitude masks on the market and avoids the use of high resolution motorized stages, as is the case of the point-by-point technique. Finally, the 3D printed masks were also used to induce LPGs using the mechanical pressing method. Due to the better resolution of these masks compared to ones described on the state of the art, we were able to induce gratings with higher quality, such as low out-of-band loss (0.6 dB), reduced spectral ripples, and narrow bandwidths (~3 nm).

scholarly journals Phosphatidylserine-Gold Nanoparticles (PS-AuNP) Induce Prostate and Breast Cancer Cell Apoptosis

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1094
Author(s):  
Allan Radaic ◽  
Nam E. Joo ◽  
Soo-Hwan Jeong ◽  
Seong-II Yoo ◽  
Nicholas Kotov ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gold Nanoparticles ◽  
Biomedical Applications ◽  
Therapeutic Potential ◽  
Control Treatment ◽  
Track Record ◽  
Males And Females ◽  
Breast And Prostate Cancer ◽  
First Time

Prostate and breast cancer are the current leading causes of new cancer cases in males and females, respectively. Phosphatidylserine (PS) is an essential lipid that mediates macrophage efferocytosis and is dysregulated in tumors. Therefore, developing therapies that selectively restore PS may be a potential therapeutic approach for carcinogenesis. Among the nanomedicine strategies for delivering PS, biocompatible gold nanoparticles (AuNPs) have an extensive track record in biomedical applications. In this study, we synthesized biomimetic phosphatidylserine-caped gold nanoparticles (PS-AuNPs) and tested their anticancer potential in breast and prostate cancer cells in vitro. We found that both cell lines exhibited changes in cell morphology indicative of apoptosis. After evaluating for histone-associated DNA fragments, a hallmark of apoptosis, we found significant increases in DNA fragmentation upon PS-AuNP treatment compared to the control treatment. These findings demonstrate the use of phosphatidylserine coupled with gold nanoparticles as a potential treatment for prostate and breast cancer. To the best of our knowledge, this is the first time that a phosphatidylserine-capped AuNP has been examined for its therapeutic potential in cancer therapy.

scholarly journals Facile Green, Room-Temperature Synthesis of Gold Nanoparticles Using Combretum erythrophyllum Leaf Extract: Antibacterial and Cell Viability Studies against Normal and Cancerous Cells

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 893
Author(s):  
Olufunto T. Fanoro ◽  
Sundararajan Parani ◽  
Rodney Maluleke ◽  
Thabang C. Lebepe ◽  
Jose R. Varghese ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Cell Viability ◽  
Leaf Extract ◽  
Room Temperature ◽  
Klebsiella Oxytoca ◽  
Cost Effective ◽  
Average Diameter ◽  
Antibacterial Activities ◽  
Inhibition Concentration ◽  
First Time

We herein report a facile, green, cost-effective, plant-mediated synthesis of gold nanoparticles (AuNPs) for the first time using Combretum erythrophyllum (CE) plant leaves. The synthesis was conducted at room temperature using CE leaf extract serving as a reducing and capping agent. The as-synthesized AuNPs were found to be crystalline, well dispersed, and spherical in shape with an average diameter of 13.20 nm and an excellent stability of over 60 days. The AuNPs showed broad-spectrum antibacterial activities against both pathogenic Gram-positive (Staphylococcus epidermidis (ATCC14990), Staphylococcus aureus (ATCC 25923), Mycobacterium smegmatis (MC 215)) and Gram-negative bacteria (Proteus mirabilis (ATCC 7002), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13822), Klebsiella oxytoca (ATCC 8724)), with a minimum inhibition concentration of 62.5 µg/mL. In addition, the as-synthesized AuNPs were highly stable with exceptional cell viability towards normal cells (BHK- 21) and cancerous cancer cell lines (cervical and lung cancer).

Gap solitons supported by an optical lattice in biased photorefractive crystals having both the linear and quadratic electro-optic effect

2020 ◽  
Vol 75 (8) ◽  
pp. 749-756
Author(s):  
Aavishkar Katti ◽  
Chittaranjan P. Katti
Keyword(s):  
Band Gap ◽  
Optical Lattice ◽  
Propagation Constant ◽  
Gap Soliton ◽  
Electro Optic ◽  
Quadratic Nonlinearities ◽  
Existence And Stability ◽  
Gap Solitons ◽  
Finite Band ◽  
First Time

AbstractWe investigate the existence and stability of gap solitons supported by an optical lattice in biased photorefractive (PR) crystals having both the linear and quadratic electro-optic effect. Such PR crystals have an interesting interplay between the linear and quadratic nonlinearities. Gap solitons are predicted for the first time in such novel PR media. Taking a relevant example (PMN-0.33PT), we find that the gap solitons in the first finite bandgap are single humped, positive and symmetric solitons while those in the second finite band gap are antisymmetric and double humped. The power of the gap soliton depends upon the value of the axial propagation constant. We delineate three power regimes and study the gap soliton profiles in each region. The gap solitons in the first finite band gap are not linearly stable while those in the second finite band gap are found to be stable against small perturbations. We study their stability properties in detail throughout the finite band gaps. The interplay between the linear and quadratic electro-optic effect is studied by investigating the spatial profiles and stability of the gap solitons for different ratios of the linear and quadratic nonlinear coefficients.

scholarly journals Surface-Initiated Atom Transfer Polymerized Anionic Corona on Gold Nanoparticles for Anti-Cancer Therapy

Pharmaceutics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 261
Author(s):  
Wei Mao ◽  
Sol Lee ◽  
Ji Un Shin ◽  
Hyuk Sang Yoo
Keyword(s):  
Gold Nanoparticles ◽  
Transfection Efficiency ◽  
Cancer Therapeutics ◽  
Atom Transfer ◽  
Layer By Layer ◽  
Dependent Manner ◽  
Metallic Particles ◽  
Anti Cancer

Surface initiated atom transfer radical polymerization (SI-ATRP) documented a simple but efficient technique to grow a dense polymer layer on any surface. Gold nanoparticles (AuNPs) give a broad surface to immobilize sulfhyryl group-containing initiators for SI-ATRP; in addition, AuNPs are the major nanoparticulate carriers for delivery of anti-cancer therapeutics, since they are biocompatible and bioinert. In this work, AuNPs with a disulfide initiator were polymerized with sulfoethyl methacrylate by SI-ATRP to decorate the particles with anionic corona, and branched polyethyeleneimine (PEI) and siRNA were sequentially layered onto the anionic corona of AuNP by electrostatic interaction. The in vitro anti-cancer effect confirmed that AuNP with anionic corona showed higher degrees of apoptosis as well as suppression of the oncogene expression in a siRNA dose-dependent manner. The in vivo study of tumor-bearing nude mice revealed that mice treated with c-Myc siRNA-incorporated AuNPs showed dramatically decreased tumor size in comparison to those with free siRNA for 4 weeks. Furthermore, histological examination and gene expression study revealed that the decorated AuNP significantly suppressed c-Myc expression. Thus, we envision that the layer-by-layer assembly on the anionic brushes can be potentially used to incorporate nucleic acids onto metallic particles with high transfection efficiency.

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