scholarly journals Strategies for Dielectric Contrast Enhancement in 1D Planar Polymeric Photonic Crystals

2020 ◽  
Vol 10 (12) ◽  
pp. 4122
Author(s):  
Paola Lova ◽  
Heba Megahd ◽  
Paola Stagnaro ◽  
Marina Alloisio ◽  
Maddalena Patrini ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
High Refractive Index ◽  
Polymer Structure ◽  
Melt Processing ◽  
Air Voids ◽  
Light Confinement ◽  
Low Dielectric ◽  
Dielectric Contrast ◽  
Light Management ◽  
The Common

Historically, photonic crystals have been made of inorganic high refractive index materials coupled to air voids to maximize the dielectric contrast and in turn the light confinement. However, these systems are complex, costly, and time-demanding, and the fabrication processes are difficult to scale. Polymer structures promise to tackle this issue thanks to their easy solution and melt processing. Unfortunately, their low dielectric contrast limits their performance. In this work, we propose a concise but exhaustive review of the common polymers employed in the fabrication of planar 1D photonic crystals and new approaches to the enhancement of their dielectric contrast. Transfer matrix method modeling will be employed to quantify the effect of this parameter in standardized structures and to propose a new polymer structure for applications dealing with light management.

scholarly journals High Refractive Index Inverse Vulcanized Polymers for Organic Photonic Crystals

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 154 ◽  
Author(s):  
Christian Tavella ◽  
Paola Lova ◽  
Martina Marsotto ◽  
Giorgio Luciano ◽  
Maddalena Patrini ◽  
...  
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Photonic Band Gap ◽  
High Refractive Index ◽  
Melt Processing ◽  
Added Value ◽  
New Approach ◽  
Dielectric Contrast ◽  
High Dielectric ◽  
Photonic Band

Photonic technologies are nowadays dominated by highly performing inorganic structures that are commonly fabricated via lithography or epitaxial growths. Unfortunately, the fabrication of these systems is costly, time consuming, and does not allow for the growth of large photonic structures. All-polymer photonic crystals could overcome this limitation thanks to easy solubility and melt processing. On the other hand, macromolecules often do not offer a dielectric contrast large enough to approach the performances of their inorganic counterparts. In this work, we demonstrate a new approach to achieve high dielectric contrast distributed Bragg reflectors with a photonic band gap that is tunable in a very broad spectral region. A highly transparent medium was developed through a blend of a commercial polymer with a high refractive index inverse vulcanized polymer that is rich in sulfur, where the large polarizability of the S–S bond provides refractive index values that are unconceivable with common non-conjugated polymers. This approach paves the way to the recycling of sulfur byproducts for new high added-value nano-structures.

Oxa-Michael polyaddition of vinylsulfonylethanol for aliphatic polyethersulfones

2021 ◽  
Author(s):  
Nicole Ziegenbalg ◽  
Ruth Lohwasser ◽  
Giovanni D’Andola ◽  
Torben Adermann ◽  
Johannes Christopher Brendel
Keyword(s):  
Refractive Index ◽  
High Temperature ◽  
Flame Retardant ◽  
Chemical Resistance ◽  
High Refractive Index ◽  
Industrial Applications ◽  
Interesting Class ◽  
The Common ◽  
Flame Retardant Properties

Polyethersulfones are an interesting class of polymers for industrial applications due to their unusual properties such as a high refractive index, flame-retardant properties, high temperature and chemical resistance. The common...

scholarly journals Preliminary investigations of magnetic modulated nanoparticles for microwave breast cancer detection

2015 ◽  
Vol 1 (1) ◽  
pp. 302-305 ◽  
Author(s):  
S. Ley ◽  
M. Helbig ◽  
J. Sachs
Keyword(s):  
Cancer Detection ◽  
Breast Imaging ◽  
Breast Cancer Detection ◽  
Ultra Wideband ◽  
Oxide Nanoparticles ◽  
Clinical Use ◽  
Low Dielectric ◽  
M Sequence ◽  
Dielectric Contrast ◽  
Signal Response

AbstractThis paper investigates the potential of magnetic modulated iron oxide nanoparticles in terms of a contrast enhancement for Ultra-wideband (UWB) breast imaging. The work is motivated by the low dielectric contrast between tumor and normal glandular/fibroconnective tissue. The influence of an external polarizing magnetic field on pure and coated magnetite nanoparticles is investigated in this contribution. Measurements were conducted using M-sequence UWB technology and an oil-gelatin phantom. It is shown that a coating, which is necessary for clinical use, results in a lower signal response, and thus leads to a lower detectability of magnetic modulated nanoparticles.

3-Dimensional Photonic Crystals at Optical Wavelengths

1998 ◽  
Vol 07 (02) ◽  
pp. 181-200 ◽  
Author(s):  
S. G. Romanov
Keyword(s):  
Photonic Crystals ◽  
Band Gap ◽  
Photonic Band Gap ◽  
Stop Band ◽  
High Refractive Index ◽  
3 Dimensional ◽  
Optical Wavelength ◽  
Photonic Band Gap Materials ◽  
Optical Wavelengths ◽  
Photonic Band

Different experimental strategies towards the 3-dimensional photonic crystals operating at optical wavelength are classified. The detailed discussion is devoted to the recent progress in photonic crystals fabricated by template method — the photonic band gap materials on the base of opal. The control of photonic properties of opal-based gratings is achieved through impregnating the opal with high refractive index semiconductors and dielectrics. Experimental study demonstrated the dependence of the stop band behaviour upon the type of impregnation (complete or partial) and showed a way for approaching complete photonic band gap. The photoluminescence from opal- semiconductor gratings revealed suppression of spontaneous emission in the gap region with following enhancement of the emission efficiency at the low-energy edge of the gap.

scholarly journals Scalable High Refractive Index polystyrene-sulfur nanocomposites via in situ inverse vulcanization

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Vijay S. Wadi ◽  
Kishore K. Jena ◽  
Kevin Halique ◽  
Brigita Rožič ◽  
Luka Cmok ◽  
...  
Keyword(s):  
Refractive Index ◽  
Low Cost ◽  
High Refractive Index ◽  
Extrusion Process ◽  
Melt Processing ◽  
Process Formation ◽  
Polystyrene Matrix ◽  
One Step ◽  
Extrusion Method

Abstract In this work, we demostrate the preparation of low cost High Refractive Index polystyrene-sulfur nanocomposites in one step by combining inverse vulcanization and melt extrusion method. Poly(sulfur-1,3-diisopropenylbenzene) (PS-SD) copolymer nanoparticles (5 to 10 wt%) were generated in the polystyrene matrix via in situ inverse vulcanization reaction during extrusion process. Formation of SD copolymer was confirmed by FTIR and Raman spectroscopy. SEM and TEM further confirms the presence of homogeneously dispersed SD nanoparticles in the size range of 5 nm. Thermal and mechanical properties of these nanocomposites are comparable with the pristine polystyrene. The transparent nanocomposites exhibits High Refractive Index n = 1.673 at 402.9 nm and Abbe’y number ~ 30 at 10 wt% of sulfur loading. The nanocomposites can be easily processed into mold, films and thin films by melt processing as well as solution casting techniques. Moreover, this one step preparation method is scalable and can be extend to the other polymers.

scholarly journals Anodic Alumina Photonic Crystals as Refractive Index Sensors for Controlling the Composition of Liquid Mixtures

2019 ◽  
Vol 10 (2) ◽  
pp. 147-154 ◽  
Author(s):  
Matin Ashurov ◽  
Vladimir Gorelik ◽  
Kirill Napolskii ◽  
Sergey Klimonsky
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Stop Band ◽  
Analytical Signal ◽  
Liquid Mixtures ◽  
High Refractive Index ◽  
Anodic Alumina ◽  
Refractive Index Sensitivity ◽  
Water Glycerol ◽  
Refractive Index Sensors

Abstract Photonic crystals based on anodic aluminum oxide films are examined as refractive index sensors for controlling the composition of water-alcohol liquid mixtures. The position of the reflectance maximum corresponding to the first photonic stop band is used as the analytical signal. Impregnation of a photonic crystal with water-ethanol and water-glycerol mixtures results in a redshift of the reflectance maximum. A fairly high refractive index sensitivity, sufficient to determine the composition of water-ethanol and water-glycerol mixtures with an accuracy of about 1 wt.%, is observed. The detailed dependencies of the analytical signal on the composition of mixtures are experimentally investigated and compared with numerical calculations. Prospects and limitations of the refractive index sensors based on anodic alumina photonic crystals are discussed.

scholarly journals Sodium Alginate Cross-Linkable Planar 1D Photonic Crystals as a Promising Tool for Pb2+ Detection in Water

Chemosensors ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 37 ◽  
Author(s):  
Andrea Dodero ◽  
Paola Lova ◽  
Silvia Vicini ◽  
Maila Castellano ◽  
Davide Comoretto
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Sodium Alginate ◽  
Spectral Response ◽  
High Refractive Index ◽  
Polluted Water ◽  
Ionic Exchange ◽  
Promising Tool ◽  
Rural Environments ◽  
First Time

Due to its high toxicity, Pb2+ pollution is a serious threat for human health and environments. However, in situ real-time detection of Pb2+ pollution is difficult and laboratory instruments are usually required. Then, the possibility to monitor water quality without laboratory instruments could lead to the extensive assessment of polluted water sources, especially in rural environments and developing countries where large lead concentrations are often found in surface water. Consequently, new simple colorimetric sensors are highly interesting in the field. In this work we report for the first time disposable polymer planar 1D photonic crystals made of poly (N-vinylcarbazole) as high refractive index medium and sodium alginate as low refractive index and active medium for the detection of Pb2+ in water. The detection relies on the ionic exchange occurring into the alginate matrix. This process effectively induces a physical cross-linking phenomenon, which inhibits water solubilization of the polymer. In turn, this affects the spectral response of the planar 1D photonic crystals modifying its color.

Sign in / Sign up

Export Citation Format

Share Document