Electronic circuits provide us with the ability to control the transport and storage of electrons. However, the performance of electronic circuits is now becoming rather limited when digital information needs to be sent from one point to another. Photonics offers an effective solution to this problem by implementing optical communication systems based on optical fibers and photonic circuits. Unfortunately, the micrometer-scale bulky components of photonics have limited the integration of these components into electronic chips, which are now measured in nanometers. Surface plasmon-based circuits, which merge electronics and photonics at the Nano scale, may offer a solution to this size-compatibility problem. Here we review the current status and future prospects of plasmonics in various applications including plasmonic chips, light generation, and nanolithography.
Electronic circuits provide us with the ability to control the transport and storage of electrons. However, the performance of electronic circuits is now becoming rather limited when digital information needs to be sent from one point to another. Photonics offers an effective solution to this problem by implementing optical communication systems based on optical fibers and photonic circuits. Unfortunately, the micrometer-scale bulky components of photonics have limited the integration of these components into electronic chips, which are now measured in nanometers. Surface plasmon-based circuits, which merge electronics and photonics at the Nano scale, may offer a solution to this size-compatibility problem. Here we review the current status and future prospects of plasmonics in various applications including plasmonic chips, light generation, and nanolithography.
Comparison of Different types of Solar Cells – a Reviewiosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Photonic crystals are periodic dielectric structures that have a band gap that forbids propagation of a certain frequency range of light. This property enables one to control light with amazing facility and produce effects that are impossible with conventional optics.Photonic crystals can be fabricated for one, two, or three dimensions. One-dimensional photonic crystals can be made of layers deposited or stuck together. Two-dimensional ones can be made by photolithography, or by drilling holes in a suitable substrate. Fabrication methods for three-dimensional ones include drilling under different angles, stacking multiple 2-D layers on top of each other, direct laser writing, or, for example, instigating self-assembly of spheres in a matrix and dissolving the spheres
Gifted Students - Material Science - The Gifted Child - Giftedness Enrichment...Lakshmi Sharma
Introduction to material science
covers relationship to areas of science
scaffolding learned and real life science - relationship to classroom science & new materials researched now
Comparison of Different types of Solar Cells – a Reviewiosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Photonic crystals are periodic dielectric structures that have a band gap that forbids propagation of a certain frequency range of light. This property enables one to control light with amazing facility and produce effects that are impossible with conventional optics.Photonic crystals can be fabricated for one, two, or three dimensions. One-dimensional photonic crystals can be made of layers deposited or stuck together. Two-dimensional ones can be made by photolithography, or by drilling holes in a suitable substrate. Fabrication methods for three-dimensional ones include drilling under different angles, stacking multiple 2-D layers on top of each other, direct laser writing, or, for example, instigating self-assembly of spheres in a matrix and dissolving the spheres
Gifted Students - Material Science - The Gifted Child - Giftedness Enrichment...Lakshmi Sharma
Introduction to material science
covers relationship to areas of science
scaffolding learned and real life science - relationship to classroom science & new materials researched now
Clay is a mineral, belonging to phyllosilicate category.
Chemically it consists of aluminium silicate as a principal component along with variety of other metals like magnesium, calcium, potassium and varying level of watermolecules.
Atomic configuration of clays consists of alternating ‘sheets’ of tetrahedral SiO4 and octahedral AlO6 units formed by oxygen sharing
Organoclay is the organically modified pyllosillicate,derived from a naturally occuring clay mineral.
By exchanging the original inter layer cations for organo cations (typically alkylammonium ions) an organophillic surface is generated, consisting of covalently linked organic moieties.
The lamellar structure remains analoguos to the parent phyllosilicate.
Separation of the layers due to ion exchange from the initial interlayer spacing of as little as 3 Å in the case of Na + cations to the distances in the range of 10 - 40 Å as well as the change of chemical character of the clay surface , allows the insitu polymerisation or mixing with certain polymers to obtain what is known as nano composite.
Exfoliation of MMT and Mica with multifunctional amine copolymers
Study of highly broadening Photonic band gaps extension in one-dimensional Me...IOSR Journals
In this paper, we show theoretically that the reflectance spectra of one dimensional multilayer metal-organic periodic structure (1D MOPS) can be enhanced due to the addition of the organic constituents. We have used simple transfer matrix method to calculate the absorption, transmittance and reflectance of the 1D MOPS systems. The organic component like N,N’-bis-(1-naphthyl)-N,N’diphenyl-1; 1biphenyl-4; 4diamine (NPB) absorbs the light in ultra-violet, visible and infrared electromagnetic region and the structure with Ag-metal also having the tendency to absorb the light by the plasmaonic action and their refractive can be calculated from Drude equation. The reflectance spectra of multilayer 1D MOPS containing a variable number periodic of Ag/N,N’-bis-(1-naphthyl)-N,N’diphenyl-1; 1biphenyl-4; 4diamine (NPB) structure are calculated taking optical constant of NPB and Ag. The optical band gap and reflectance spectra of 1D MOPS of the considered structure is obtained in the visible and near infrared regions either with the variation of the metal layer thickness or thickness of the organic layer. From the results under investigation through TMM, tunability in the optical band gap was observed either change in thickness of the other layer 1/ or 2 or the angle of the incident. Due to optical absorption of the light in the different region of electromagnetic spectrum due to either N,N’-bis-(1-naphthyl)-N,N’diphenyl-1; 1biphenyl-4; 4diamine (NPB) or silver metal, the optical band gap of 1DMOPS shows the shift of band edges of λL and λR from ultra-violet to visible and the infrared with change the optical constant.
In these work, new nano and micro thermoplastic based composite is prepared with zeolite filler, The method involves using zeolite in powder form, the preparation of zeolite powder from ores by crushing it into small - sized granules. The characteristics of the zeolite powder are determined. The physical properties and chemical composition (XRD) are evaluated before impeding it into the thermoplastic. Thermoplastics powder are added to the zeolite powder as granules in different sizes, The particles sizes ranging from the size of a millimeter to nanometer. The manufacturing quality parameters are optimized at volume percentages of filler in the range 20 to 25 % , composite material is formed into molds. New Composite material is characterized by easy deformation into different shapes beside machine ability. The characteristics of new composite such as SEM, EDX,FTIR in absorption and transmission mode are evaluated and compared with the standard characteristics of Zeolite ores. The performance and characteristics of the new composite are completely different. The new composite is hard, solid and does not absorb water. The work end with list of recommendation about the new field and expected application of Zeolite when using it as filler in thermoplastic based micro and nano composites.
Study the effect of thin film thickness on the optical features of (IR5 laser...TELKOMNIKA JOURNAL
The linear optical features such as (transmittance T, absorbance A, the effective length 퐿푒푓푓, absorption coefficient 훼 and refractive index 푛 ) for the thin films samples of (3x10-3 mol/l of (IR5) laser dye, 0.02 gm of (CdS) nanoparticles and 0.04 gm of pp polymer) had been studied at different values of film thickness in one time and at different number of Yb:GdVO4 laser pulses. The non-linear optical features in terms of transmittance difference Δ푇푝−푣, non-linear refractive index 푛2, non–linear phase shift Δ훷표 non-linear absorption coefficient 훽 and minimum normalized transmittance 푇(푍) have been computed in relation to obtained normalized transmittance data from setup of Z-scan with open and closed apertures, calculated for (3x10-3 mol/l of (IR5) laser dye, 0.02 gm of (CdSe) nanoparticles and 0.04 gm of (pp) polymer) thin films at different values of film thickness at in one time and at different Yb:GdVO4 laser pulses. Thick films causes in deleting the non-linear effects generated by different layers. The (CdSe) nanoparticles leads to an absorption shifting of the wavelengths to lengthier wavelengths of red shift. So, this can be used in selecting the nanoparticles and medium with applicable exciting wavelengths. The film thickness and the laser pulses have the main effects in consolidating the Non-linear optical features.
Design and analysis of multicolor qdip based on metallic nanoslits array modi...University of Technology
Design and Analysis of Multicolor QDIP Based
on Metallic Nanoslits Array
Alireza Mobini and Vahid Ahmadi, Senior Member, IEEE
its a view of their work.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
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The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
How to Make a Field invisible in Odoo 17Celine George
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Model Attribute Check Company Auto PropertyCeline George
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Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Plasmonic assisted optical absorption enhancement in thin films, a theoretical perspective
1. Plasmonic assisted optical absorption
enhancement in thin films
a theoretical perspective
Aparajita Mandal
JRF, department of ERU
Indian Association for the Cultivation of Science
3. Plasmonics
Localized Surface plasmon:
The stationary oscillation of conduction electrons confined
on a nano sized metal boundary under the excitation of
electromagnetic field.
5. • Plasmonics: Particle Size dependence
Electrostatics
+
++ ++
Dipolar mode
R<< λ
-- - - Phase retardation
across the volume
R ≈λ
-
-
+
+
+
+
--
Electrodynamics
Higher order
mode
6. Advantages
• Local field enhancement (Light can be confined to a volume which is much
smaller the wavelength).
•
Enhanced light scattering
( eff g )
• Tunability over the optical properties (such as resonance frequency, forward or
backward scattering, bandwidth) of the nano particles by controlling the size, shape
and dielectric environment.
7. ICSEP
19-21 dec. 2012
Mie Theory
Overall scattering or absorption cross section σ scat/abs for a single NP as a sum of the
contribution from all the normal modes supported by the particles.
scat / abs
scat / abs
n
n 1
Where σ n scat/abs is the contribution of the nth normal mode.
Theoretically infinite number of plasmon modes is possible….
For very small particles , contribution of only dipolar (DP) mode (n = 1 ) is effective.
As particle size increases, higher order modes (e.g. n = 2 corresponds to quadrupole and
so on) gradually start to dominate the extinction spectra.
8. ICSEP
19-21 dec. 2012
Effects of higher order modes on extinction spectra
Higher order modes introduce additional peaks at shorter wavelengths than
dipolar peak.
9. ICSEP
19-21 dec. 2012
•
For an array of MNPs
Electromagnetic coupling exists between MNPs, strength of which is
determined by the interparticle seperation.
+
+
-
+
-
-
+
Nature of interaction is dependent on polarization of incident light
10. ICSEP
19-21 dec. 2012
Effect of inter-particle coupling on extinction
spectra
•
Redshift or blue shift of resonance wavelength.
•
Nature of shift depends on the increase or decrease in the restoring
force of oscillating electron cloud.
•
spectral overlap between different modes.
11. Absorption Enhancement in thin films
•
In thin film solar cells such as amorphous silicon (a-Si:H) solar cells the
intrinsic layer need to be thin ( 300nm) in order to reduce the light
induced degradation.
• This thickness restriction results in reduced absorption of the solar
spectrum and low short circuit current of such solar cells.
•
Plasmonics is a promising way of enhancing light absorption within the
thin absorber layer.
12. ICSEP
19-21 dec. 2012
Goal of the Present work
To determine the overall contribution on the optical absorption enahncement within an
hydrogenated amorphous silicon film (a-Si:H) of thickness 200nm of front patterned Ag
MNPs having size of the order of visible wavelength.
Going beyond dipolar contribution on absorption : Ag MNPs are large enough to
support higher order plasmon modes.
To investigate how coupling between the MNPs modifies the higher order modes and
thereby influencing the absorption.
Understanding the role of Spacer layer thickness for front patterning.
Usefulness of large MNPs.
13. Ag nano particles array for enhancing light absorption within the aSi:H thin film
Plane wave
illumination
Ag MNPs
2R
D
SiO2
a-Si:H
Structure used for simulation using Finite Difference Time Domain (FDTD)
Method that solves Maxwell’s curl equations of electromagnetism
Parameters: R, D, surface coverage, SiO2 thickness, shape and type of
metal nano particles (Ag, Au or Al).
14. ICSEP
19-21 dec. 2012
FDTD simulation span
Simulation Model
PML
PBC
Periodic Boundary Condition (PBC)
models the periodicity of the MNPs in
X and Y directions.
PBC
PBC
PBC
It also takes into account interparticle
coupling effect.
Plane wave
illumination
Ag MNPs
SiO2
a-Si:H
Perfectly Matched Layer (PML)
prevents any non physical reflections
from Z direction.
PML
Schematic of the structure simulated using
FDTD method
15. ICSEP
19-21 dec. 2012
Results
Fraction of light absorbed (Pabs (λ)) with respect to wavelength (λ)
Figure 1. For the array of Ag nano particles with radii R
and constant surface coverage of 31 %.
Figure 2. For the array of Ag nano particles with radii R and
constant array period of 350 nm. Covergae factor changes
from 31 % to 58 %.
17. ICSEP
19-21 dec. 2012
Interpretations
Increases the surface coverage from 31% to 58% increases the electromagnetic
coupling between the L-MNPs .
As a result, the distinct DP and QP peak in the scattering spectra combines together
resulting in a cooperative spectral property [1] that produces a single and broad spectral
absorption peak within the a-Si:H layer.
Redshift in figure 1 is associated with both the effect of changing R and D.
18. ICSEP
19-21 dec. 2012
Results
Total Integrated absorption
To comprehend the optical absorption due to AM1.5G solar
radiation, we have calculated the total integrated absorption as,
P
T
800
I P d
abs
400
I (λ) describes the irradiance of AM1.5G at λ.
19. ICSEP
19-21 dec. 2012
Observations
We observe a second maxima (PST) in PT.
If we consider PT for a wide range of R
from 40 nm -200 nm, there will be two
peaks : One occuring for smaller R that
have dipole dominated extinction spectra
[2] , another (PST) for larger R
supporting higher order modes .
Position of PST with respect to R changes
with D.
Total integrated absorption PT as a function of Ag nano particle radii
for array period (a) 350 nm (b) 380 nm (c) 400 nm (d) 450 nm.
PST indicates the second maxima due to higher order modes.
r denotes PT in bare a-Si:H (without MNPs)
We attribute the occurrence of PST as resulting from the optimum coupling
between the higher order modes of L-MNPs depending upon the values of D.
20. ICSEP
19-21 dec. 2012
Results
Absorption enhancement over the visible spectrum
Absorption enhancement,
Enhancement throughout broad spectrum
Pabs
Pb ( )
Enhancement within narrow wavelengths band
ɳ˂1 is represented as black regions
21. Role of SiO2 (spacer layer) thickness
SiO2
Optimum Optimum
Total
thickness Radius
Period Integrated
(nm)
(nm)
(nm)
Absorption
(Watt m-2)
0
75
400
191.6
2
65
350
201.58
20
65
400
196.14
For nano particles having fixed geometrical cross section, increase in SiO2 layer
thickness:
•
•
Increases the effective scattering cross section of the NPs.
Decreases the coupling fraction of scattered light into the a-Si:H layer.
Therefore, there exists an optimum spacer layer thickness [Table.1].
t =0
t = 2 nm
t = 20 nm
22. Choice of metal:
Comparison between Ag, Au and Al
Absorption Enhancement
1.4
1.2
Al
Au
Ag
1.0
0.8
0.6
400
450
500
550
600
650
700
750
wavelength (nm)
Proper choice of metal depending on the absorption enhancement in the desired
wavelength range can be made.
23. ICSEP
19-21 dec. 2012
Conclusion
•
There is significant contribution of quadrupolar mode in optical
absorption.
•
Using the size characteristics of dipolar and quadrupolar plasmon modes
and their dependence on the array period, it is possible to tailor position
of absorption peaks.
•
The enhancement may be tuned to occur either over a broad spectral
range or as a narrow band as demanded for the device application.
•
Aluminum would be a promising candidate in plasmonic solar cell
applications as it can provide efficient absorption enhancement in
the visible wavelength range.
24. Publications:
Jounal publication:
1. Aparajita Mandal and Partha Chaudhuri, Size and period optimization of front
pattered interactiong metal nanoparticles for maximizing absorption of solar
radiation in amorphous silicon thin films, J. Opt. 14 (2012) 065001 (6pp).
2. Aparajita Mandal, Partha Chaudhuri, Journal of Renewable and Sustainable
Energy 5, 031614, 2013.
3. Aparajita Mandal and Partha Chaudhuri, “Contribution of higher order plasmonic
modes on optical absorption enhancement in amorphous silicon thin films”,
Volume 300, Pages 77–84, 2013.
Conference Proceedings:
1. Aparajita Mandal and Partha Chaudhuri, Simulation of optical absorption
enhancement in amorphous silicon using front surface patterning with metal
nanostructures, Energy and Eco friendly Materials, December 12-16th,
Coimbatore, India, page 67-70, Macmillan Advanced Research Series.
26. Additional details…..
Scattering cross section ( ) with respect to wavelength of a single Ag
nano particle in air as a function of radius . Dipolar (DP),
Quadrupolar (QP) and Octupolar (OP) resonances are indicated.
Plasmonic contribution in optical absorption within a 200 nm thick aSi:H layer as a function of wavelength for an array of Ag nano particles
radii of (a) 135 nm and (b) 65 nm. Peaks in due to the dominating
dipolar (DDP) and quadrupolar mode (DQP) is shown.