Abstract: Silicon carbide based 1-D Photonic crystals with 2 layered unit cell are analyzed in this paper. The transmission characteristics of photonic crystals are computed by transfer matrix method and performance of such photonic crystals of different material combinations are also compared, and after comparison some one able to know the characteristics such as pass band width, stop band width, centre band gap of a light wave of a particular wave length traveling through this 2 layered unit cell photonic crystal in nano meter range where one layer of this unit cell must be made of semiconductor material named silicon carbide (SiC). Key word: 1-D photonic crystal, transmission coefficient, light wave
STUDY ON THE ABSORPTION AND SCATTERING EFFICIENCIES OF THE CADMIUM TELLURIDE ...IJAMSE Journal
The optical properties of cadmium telluride nanowires have been simulated using the Mie scattering
coefficients. It is seen that the absorption efficiency shows multiple peaks along the spectrum due to leaky
mode resonance. The nanowires showed strong polarization dependence in smaller radius. Higher angle of
incidence showed a suppressing effect on lower valued peaks on absorption efficiency. Scattering efficiency
showed peaks at visible spectrum from 30nm to 100nm. Transverse magnetic wave showed a more
pronounced effect in scattering than transverse electric wave.
Two efficient algorithms for drawing accurate and beautiful phonon dispersionTakeshi Nishimatsu
Purpose: easy drawing of accurate and beautiful phonon dispersion in first-principles calculations
See also: Draw phonon dispersion of Si with Quantum Espresso https://gist.github.com/t-nissie/32c10a148a7fc054b836
Macro-Bending Loss of Single-Mode Fiber beyond Its Operating WavelengthTELKOMNIKA JOURNAL
A standard telecommunication-grade single-mode optical fiber is designed to have a
low macro-bending loss in its entire operating wavelengths to comply with the ITU-T
Recommendation G.652. In this paper, we described the potential use of such a fiber as an
intensity-based sensor due to the macro-bending loss as an alternative to using a bendingsensitive
fiber. We calculated the macro-bending loss of several single-mode optical fiber
patchcords using the classical Marcuse equation at several wavelengths, and measured its
transmission loss due to bending using an optical spectrum analyzer. For each type of fibers
there is a wavelength with a significant macro-bending loss of the LP11 mode when the Vnumber
of the fiber lies between 2.4 and 4, and that of the LP01 mode when the V-number of the
fiber lies between 1 and 2.4. This work shows a thorough mathematical and experimental
analysis for the posibility in using standard telecommunication fibers for intensity based-fiber
sensor taking the benefit of bending loss phenomenon using commercial light sources.
STUDY ON THE ABSORPTION AND SCATTERING EFFICIENCIES OF THE CADMIUM TELLURIDE ...IJAMSE Journal
The optical properties of cadmium telluride nanowires have been simulated using the Mie scattering
coefficients. It is seen that the absorption efficiency shows multiple peaks along the spectrum due to leaky
mode resonance. The nanowires showed strong polarization dependence in smaller radius. Higher angle of
incidence showed a suppressing effect on lower valued peaks on absorption efficiency. Scattering efficiency
showed peaks at visible spectrum from 30nm to 100nm. Transverse magnetic wave showed a more
pronounced effect in scattering than transverse electric wave.
Two efficient algorithms for drawing accurate and beautiful phonon dispersionTakeshi Nishimatsu
Purpose: easy drawing of accurate and beautiful phonon dispersion in first-principles calculations
See also: Draw phonon dispersion of Si with Quantum Espresso https://gist.github.com/t-nissie/32c10a148a7fc054b836
Macro-Bending Loss of Single-Mode Fiber beyond Its Operating WavelengthTELKOMNIKA JOURNAL
A standard telecommunication-grade single-mode optical fiber is designed to have a
low macro-bending loss in its entire operating wavelengths to comply with the ITU-T
Recommendation G.652. In this paper, we described the potential use of such a fiber as an
intensity-based sensor due to the macro-bending loss as an alternative to using a bendingsensitive
fiber. We calculated the macro-bending loss of several single-mode optical fiber
patchcords using the classical Marcuse equation at several wavelengths, and measured its
transmission loss due to bending using an optical spectrum analyzer. For each type of fibers
there is a wavelength with a significant macro-bending loss of the LP11 mode when the Vnumber
of the fiber lies between 2.4 and 4, and that of the LP01 mode when the V-number of the
fiber lies between 1 and 2.4. This work shows a thorough mathematical and experimental
analysis for the posibility in using standard telecommunication fibers for intensity based-fiber
sensor taking the benefit of bending loss phenomenon using commercial light sources.
Los días 22 y 23 de junio de 2016 organizamos en la Fundación Ramón Areces un simposio internacional sobre 'Materiales bidimensionales: explorando los límites de la física y la ingeniería'. En colaboración con el Massachusetts Institute of Technology (MIT), científicos de este prestigioso centro de investigación mostraron las propiedades únicas de materiales como el grafeno, de solo un átomo de espesor, y al mismo tiempo más resistente que el acero y mucho más ligero.
Design of a Selective Filter based on 2D Photonic Crystals Materials IJECEIAES
Two dimensional finite differences temporal domain (2D-FDTD) numerical simulations are performed in cartesian coordinate system to determine the dispersion diagrams of transverse electric (TE) of a two-dimension photonic crystal (PC) with triangular lattice. The aim of this work is to design a filter with maximum spectral response close to the frequency 1.55 μm. To achieve this frequency, selective filters PC are formed by combination of three waveguides W 1 K A wherein the air holes have of different normalized radii respectively r 1 /a=0.44, r 2 /a=0.288 and r /a= 0.3292 (a: is the periodicity of the lattice with value 0.48 μm). Best response is obtained when we insert three small cylindrical cavities (with normalized radius of 0.17) between the two half-planes of photonic crystal strong lateral confinement.
This research, presented at the 2014 APS March Meeting in Denver, Colorado, characterizes magnetic phase transitions in the manganese-doped dichalcogenide TaS2.
Los días 22 y 23 de junio de 2016 organizamos en la Fundación Ramón Areces un simposio internacional sobre 'Materiales bidimensionales: explorando los límites de la física y la ingeniería'. En colaboración con el Massachusetts Institute of Technology (MIT), científicos de este prestigioso centro de investigación mostraron las propiedades únicas de materiales como el grafeno, de solo un átomo de espesor, y al mismo tiempo más resistente que el acero y mucho más ligero.
Design of a Selective Filter based on 2D Photonic Crystals Materials IJECEIAES
Two dimensional finite differences temporal domain (2D-FDTD) numerical simulations are performed in cartesian coordinate system to determine the dispersion diagrams of transverse electric (TE) of a two-dimension photonic crystal (PC) with triangular lattice. The aim of this work is to design a filter with maximum spectral response close to the frequency 1.55 μm. To achieve this frequency, selective filters PC are formed by combination of three waveguides W 1 K A wherein the air holes have of different normalized radii respectively r 1 /a=0.44, r 2 /a=0.288 and r /a= 0.3292 (a: is the periodicity of the lattice with value 0.48 μm). Best response is obtained when we insert three small cylindrical cavities (with normalized radius of 0.17) between the two half-planes of photonic crystal strong lateral confinement.
This research, presented at the 2014 APS March Meeting in Denver, Colorado, characterizes magnetic phase transitions in the manganese-doped dichalcogenide TaS2.
Speech Recognized Automation System Using Speaker Identification through Wire...IOSR Journals
This paper discusses the methodology for a project named “Speech Recognized Automation System
using Speaker Identification through wireless communication”. This project gives the design of Automation
system using wireless communication and speaker recognition using Matlab code. Straightforward
programming interface of Matlab makes it an ideal tool for speech analysis in project. This automation system
is useful for home appliances as well as in industry. This paper discusses the overall design of a wireless
automation system which is built and implemented. The speech recognition centers on recognition of speech
commands stored in data base of Matlab and it is matched with incoming voice command of speaker. Mel
Frequency Cepstral Coefficient (MFCC) algorithm is used to recognize the speech of speaker and to extract
features of speech. It uses low-power RF ZigBee transceiver wireless communication modules which are
relatively cheap. This automation system is intended to control lights, fans and other electrical appliances in a
home or office using speech commands like Light, Fan etc. Further, if security is not big issue then Speech
processor is used to control the appliances without speaker identification
ABSTRACT: The direct current photoconductivity of the powdered silicon and photovoltaic effect in the monocrystallic silicon are investigated. It is shown that organic dyes on the semiconductor surface effectively increase the internal photo effect in the dye absorption band. The photoconductivity of dyed powdered samples in the absorption range of the dyes is higher than the photoconductivity of undyed silicon by more than an order of magnitude. The optimum concentration of dye molecules on the monocrystal surface for a sensitization is 3×1015 cm -2 , which corresponds to the dye film thickness of about 30 monolayers or 10-15 nanometers
Measurement of energy loss of light ions using silicon surface barrier detectoreSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
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.
Maidana - Modification of particle accelerators for cargo inspection applicat...Carlos O. Maidana
As part of an accelerator based Cargo Inspection System, studies were made to develop a Cabinet Safe System by Optimization of the Beam Optics of Microwave Linear Accelerators of the IAC-Varian series working on the S-band and standing wave pi/2 mode. Measurements, modeling and simulations of the main subsystems were done and a Multiple Solenoidal System was designed.
This Cabinet Safe System based on a Multiple Solenoidal System minimizes the radiation field generated by the low efficiency of the microwave accelerators by optimizing the RF waveguide system and by also trapping secondaries generated in the accelerator head. These secondaries are generated mainly due to instabilities in the exit window region and particles backscattered from the target. The electron gun was also studied and software for its right mechanical design and for its optimization was developed as well. Besides the standard design method, an optimization of the injection process is accomplished by slightly modifying the gun configuration and by placing a solenoid on the waist position while avoiding threading the cathode with the magnetic flux generated.
The Multiple Solenoidal System and the electron gun optimization are the backbone of a Cabinet Safe System that could be applied not only to the 25 MeV IAC-Varian microwave accelerators but, by extension, to machines of different manufacturers as well. Thus, they constitute the main topic of this paper.
DEVELOPMENT OF OPTICAL PARAMETER CALCULATIONS OF THE PROBES IN WATERDr. Ved Nath Jha
Fiber optic technology with the role of surface plasmons has tremendously advanced the sensing technique of various physical, chemical and biochemical parameters of materials. The working of the optical fiber sensor designed by us is founded on the principle of the absorption of the evanescent waves passing through the optical fiber. The technique is based on the evanescent wave penetration between two dielectric media satisfying the conditions of attenuated total internal reflections (ATR’s). In the present work, the cladding of the fiber is removed by a suitable technique, and Silver nanoparticles are deposited on it. The evanescent light waves passing out of the core of the fiber are absorbed by the metal nanoparticles. The wavelength of maximum absorption is specific to the metal nanoparticles as well as to the dielectric constant of the surrounding medium and occurs when the wavelength of evanescent light resonates with localized surface plasmon (LSP) wavelength of the nanoparticle. Noble metal nanoparticles of Silver and Gold exhibit LSP resonance in the visible region of electromagnetic spectrum. In this article, we report the characteristic parameters of three sensor probes a, b and c developed by researcher.
An analytical method with numerical results to be used in the design of optic...nooriasukmaningtyas
This study develops an analytical method with numerical results for the design of optical slab waveguides for optical communication system applications. An optical slab waveguide structure made of silicon on silicon dioxide material is designed and analyzed. The effective index of the mode is studied against variations in the waveguide dimensions. Transmission and reflection coefficients are studied and compared to the wavelength and dimensions of the waveguide. Variations are sketched with the x-axis, in addition to the electric field intensity distribution and effective refractive index. Waveguide bending loss is also studied with waveguide thickness and length variations within three waveguide transmission windows of 850 nm, 1300nm, and 1550nm.
The Modulation Transfer Function (MTF) of Polycrystalline Mercuric Iodide based flat panel
x-ray detectors is simulated as a function of spatial frequency. A simplified mathematical model for MTF is
applied on four different published prototypes of Polycrystalline Mercuric Iodide. Our aim was to fit curve from
MTF model with the curve from experimental data. The result of simulation from theoretical model shows a
good agreement with the measured data. We have found that deep-trapping,K-fluorescence,dependence of dark
current on temperature and exposure time are the most possible reasons for the slight mismatches between two
curves. In addition, the mobility-lifetime product for best curve fitting was also examined for each prototype.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
X-raydiffraction has a very significant role in crystal determination.. specially in the field of Pharmaceutical analysis.
It contains the requirement for M.pharm 1st year according to RGUHS syllabus.
Analysis Of Carbon Nanotubes And Quantum Dots In A Photovoltaic Device Slide ...M. Faisal Halim
Francis' presentation to Louis Stokes Association for Minority Participation. Since I co-authored this work I think I have the right to a copy. I was the graduate student Francis was working with.
Similar to Characteristics analysis of silicon carbide based 1-D Photonic crystal with 2 layered unit cell using MATLAB (20)
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
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About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
Characteristics analysis of silicon carbide based 1-D Photonic crystal with 2 layered unit cell using MATLAB
1. IOSR Journal of Electronics and Communication Engineering (IOSR-JECE)
e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 5, Issue 6 (Mar. - Apr. 2013), PP 34-40
www.iosrjournals.org
www.iosrjournals.org 34 | Page
Characteristics analysis of silicon carbide based 1-D Photonic
crystal with 2 layered unit cell using MATLAB
Avik Chakraborty
Assistant Professor, Electronics & Communication Engg. Dept., Bengal Institute of Technology & Management,
Bolpur, Birbhum. Contact Address: Senpara, Kalitala Road, PO+Dist- Jalpaiguri, Pin-735101, West Bengal,
Abstract: Silicon carbide based 1-D Photonic crystals with 2 layered unit cell are analyzed in this paper. The
transmission characteristics of photonic crystals are computed by transfer matrix method and performance of
such photonic crystals of different material combinations are also compared, and after comparison some one
able to know the characteristics such as pass band width, stop band width, centre band gap of a light wave of a
particular wave length traveling through this 2 layered unit cell photonic crystal in nano meter range where one
layer of this unit cell must be made of semiconductor material named silicon carbide (SiC).
Key word: 1-D photonic crystal, transmission coefficient, light wave.
I. Introduction
In this paper first to know about photonic crystal [1] the statement is like that periodic optical
nanostructures that are designed to affect the motion of photons in a similar way that periodicity of a
semiconductor crystal affects the motion of electrons. such photonic crystals with photonic band gap (for some
frequency range, a photonic crystal prohibits the propagation of electromagnetic waves of any polarization
travelling in any direction from any source, then we say that the crystal has a complete photonic band gap)
preventing light from propagating in certain directions with specified frequencies In order to construct these
crystals in the optical regime, suitable nanofabrication techniques have to be developed and demonstrated,
including high resolution electron beam lithography and anisotropic chemically assisted ion beam etching.
These periodic dielectric structures are expected to exhibit interesting properties in both fields of physics and
engineering. Silicon Carbide (SiC) being an important semiconductor in the situation. The basic characteristics
of Silicon Carbide (SiC) – based photonic crystals will be analyzed .
II. One Dimensional Photonic Crystal (Phc)
In a 1-D Photonic Crystal layers of different dielectric constant may be deposited or adhered together
to form a band gap in a single direction .A Bragg grating is an example of this type of photonic crystal .This
type of photonic crystal systems exhibits three important phenomena i) Photonic Band gap , ii)Localized mode
iii) surface state ,because the index contrast is only along one direction , the band gaps and bound states are
limited to that direction .By the help of this concept this characteristics analysis is being processed.
Fig (1)-1-D Photonic Crystal
III. Reason behind the choosing of Silicon Carbide (SiC) as a semiconductor material
SiC (wide forbidden energy gap of 2.86 eV@ 302 K) has been emerged as an attractive substrate for
high power devices due to its larger band gap , higher break down strength , high thermal conductivity and high
electron saturation drift velocity. Most important advantage of SiC over other wide band gap semiconductor is
that SiC can be thermally oxidized to form an insulator Silicon die oxide. Although the refractive index of SiC is
lower than that of a conventional semiconductor such as GaAs or Si , a wide photonic band gap , a broadband
wave guide and a high quality nanocavity comparable to those of previous photonic crystals can be obtained in
Silicon Carbide based photonic crystals, for above many reason in this analysis process we choose SiC.
Description
2. Characteristics analysis of silicon carbide based 1-D
www.iosrjournals.org 35 | Page
In this paper unit cell photonic crystal has been considered which has 2 layers. The refractive indices (n1, n2) of
the two materials are related to the thickness of the layers (d1, d2) as
n1d1=n2d2=λ0/4 ………………………………………….. (1)
Where λ0= Free space (vacuum) wavelength, whose value is taken here as 1550 nanometer, since it is
the most important wavelength for optical communication.
When an electromagnetic wave with S-polarization incidents on a unit cell of two materials a and b, the
reflection and transmission coefficient can be expressed as [2]
…………….(2)
………….... (3)
Where A is the complex amplitude of the electric field, α and β are angle of incidence and refraction at
the interface.
Here S- polarized wave has its electric field vector confined perpendicular to the plane of incidence. Here
electric field E is in the y direction, so Ẽ = (0,A,0). Using S-polarization [equation (2) and (3)] we get the
equation (4)
………….(4)
And
……....(5)
Fig-(2)- Standard 2 layered unit cell Photonic Crystal
a and b indicates the two layers with refractive indices n1 and n2.
3. Characteristics analysis of silicon carbide based 1-D
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From the figure 2, First layer is for denser material and other one is for rarer material. d1 and d2 are the thickness
of each layer. Cm is the amplitude in the mth
layer for waves and Cm-1 is for m-1 layer that is first layer.
Am is the amplitude in the mth
layer for waves and Am-1 is the amplitude in the m-1 layer. From
equation (4 ) & (5) it is possible to construct transfer matrix ,here cosine value is 0 for all cases (consider) and
µ=1 in all cases but € value is changed for different material. Here m-1 layer signify the first layer and m is for
second layer of an unit cell photonic crystal. By help of equation (4) and (5) first have to construct a standard
unit cell whose two layers are made with Si and SiO2, after that just have to change the material from standard
one and place SiC on that particular position and analyze the characteristics for different material combination
where SiC is a common one.
The matrix form is like that
M=
Here zm = d2 and zm1 = d1, the general form of equation for Transfer matrix M shown in below through which
transmission coefficient can be achieved.
…………………………………. (6)
If we apply the particular transmission coefficient for 10 numbers of unit cells then transmission coefficient of
entire photonic crystal can be achieved.
To apply 10 numbers of unit cells the standard matrix form of equation is stated below
…………………..(7)
Computation of result using different parameters
Using equation (6) transmission coefficient has been computed using matlab. For computation this paper takes
the following parameters.
Free space wavelength (λ0) = 1550 nanometer (nm)
Number of unit cell (N) = 10
d1 = Thickness of the first layer
d2 = Thickness of the second layer
n1 = Refractive index of the first layer
n2 = Refractive index of the second layer
IV. Discussion of results
Silicon_Silica:
In case of Silicon and Silica the value of n1 for Silicon is 3.5 and the value of n2 for Silica is 1.5, so by
using equation (1) thickness of the first layer (d1) = 1550/4*3.5 = 110.71 nm and thickness for the second layer
(d2) = 1550/4*1.5 = 258.33 nm.
In Silicon_Silica based photonic crystal the stop band lies in between 1250 nm to 2100 nm (Approx),
so the value of transmission coefficient is 0 within this range. We can find Stop band width = 850 nm. Here
centre band gap is at 1680 nm. Pass band lies in between 550 nm to 1250 nm (Approx), so Pass band width =
1250-550= 700 nm. The choosing wavelength is 1550 nm but centre band gap lie is at 1680 nm. So our
wavelength shifts towards the higher frequency range with respect to corresponding wavelength (λ0). After 2120
nm (Approx) find another Pass band till investigate of our range 2400 nm.
4. Characteristics analysis of silicon carbide based 1-D
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Fig3: Plot between
Wavelength(nm) Vs. Trasmission Coefficient in case of Silicon_Silica based photonic crystal containing
number of unit cells (N) = 10
Silicon_Silicon Carbide:
In the case of Silicon and Silicon Carbide the value of n1 for Silicon is 3.5 and the value of n2 for
Silicon Carbide is 2.55, so by using equation (1) thickness of the first layer (d1) = 1550/4*3.5 = 110.71 nm and
thickness for the second layer (d2) = 1550/4*2.55 = 151.96 nm.
Here transmission coefficient value is not actually 0, its value is around 0.1. The reason behind is that
the difference between the refractive index value of this two material is so small (3.50 - 2.55) = 0.95, so Stop
band does not touches the 0 line. We find Pass band lies in between 550 nm to 1390 nm (Approx), so Pass band
width= 840 nm. From graph it is clearly shown that centre band gap lie is at 1580 nm (Approx) but our working
wavelength is 1550 nm. For this reason wavelength shifts towards the higher frequency range with respect to
corresponding wavelength (λ0). Starts from 1780 nm (Approx) here find another Pass band till investigate of our
range 2400 nm.
Fig4: Plot between Wavelength(nm) Vs. Transmission Coefficient in case of Silicon_Silicon Carbide based
photonic crystal containing number of unit cells (N) = 10
Silicon_Silicon Carbide:
In that case transmission coefficient value is not actually 0, its value is around 0.1. The reason behind is
that the difference between the refractive index value of this two material is so small (3.50 - 2.55) = 0.95, so
Stop band does not touches the 0 line and has value (0.1). If we increase the number of unit cells from 10 to 30,
then Stop band range is within 1410 nm to 1730 nm (Approx), so Transmission Coefficient value is actually 0
and Stop band width is 320 nm. Pass band lies in between 550 nm to 1410 nm (Approx), so Pass band width=
860 nm. From graph it is clearly shown that centre band gap lie is at 1580 nm (Approx) but our working
wavelength is 1550 nm. For this reason wavelength shifts towards the higher frequency range with respect to
corresponding wavelength (λ0). Starts from 1730 nm (Approx) here find another Pass band till investigate of our
range 2400 nm.
5. Characteristics analysis of silicon carbide based 1-D
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Fig5: Plot between Wavelength(nm) Vs. Transmission Coefficient in case of Silicon_Silicon Carbide based
photonic crystal containing number of unit cells (N) = 30
Silicon Carbide_Air:
Here for Silicon Carbide and Air the value of n1 for Silicon Carbide is 2.55 and the value of n2 for Air
is 1, so by using equation (1) thickness of the first layer (d1) = 1550/4*2.55 = 151.96 nm and thickness for the
second layer (d2) = 1550/4*1 = 387.50 nm.
From this plot it is clearly shown that Stop band lies in between 1230 nm to 2180 nm (Approx). Within
this Stop band range transmission coefficient value is 0, here Stop band width = 2180-1230 = 950 nm. Centre
band gap is at 1680 nm. Pass band lies in between 550 nm to 1230 nm (Approx). So Pass band width = 1230 –
550 = 680 nm. We work with 1550 nm wavelength but here find centre band gap lie is at 1680 nm. So our
wavelength shifts towards the higher frequency range with respect to corresponding wavelength (λ0). After 2180
nm (Approx) we find another Pass band till investigate of our range 2400 nm.
Fig6: Plot between Wavelength(nm) Vs. Transmission Coefficient in case of Silicon Carbide_Air based
photonic crystal containing number of unit cells (N) = 10
Silicon Carbide_Silica:
In that case of Silicon Carbide and Silica the value of n1 for Silicon Carbide is 2.55 and the value of n2
for Silica is 1.5, so by using equation (1) thickness of the first layer (d1) = 1550/4*2.55 = 151.96 nm and
thickness for the second layer (d2) = 1550/4*1.5 = 258.33 nm.
Here the value of transmission coefficient is not actually 0, its value is just above the 0 the reason is
that the difference between the refractive index of that two material is so small (2.55 – 1.50) = 1.05, that’s why
it is not possible to achieve the Stop band. The Pass band lies in between 550 nm to 1320 nm (Approx), so the
Pass band width is 1320 - 550 = 770 nm. In that case choosing wavelength is 1550 nm but the centre band gap
lie is at 1600 nm. So wavelength shifts towards the higher frequency range with respect to corresponding
wavelength (λ0). After 1900 nm (Approx) the end range is 2400 nm within that region we find another Pass band
lies.
6. Characteristics analysis of silicon carbide based 1-D
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Fig7: Plot between Wavelength(nm) Vs. Transmission Coefficient in case of Silicon Carbide_Silica based
photonic crystal containing number of unit cells (N) = 10
Silicon Carbide_Silica:
Here the value of transmission coefficient is not actually 0, its value is just above the 0 the reason is
that the difference between the refractive index of that two material is so small (2.55 – 1.50) = 1.05, that’s why
it is not possible to achieve the Stop band. To achieve the Stop band we have to increase the number of unit cells
(N) from 10 to 20, then we get the actual Transmission Coefficient value 0 within the Stop band range 1320 nm
to 1870 nm (Approx), so Stop band width is 1870-1320= 550 nm. Pass band lies in between 550 nm to 1320 nm
(Approx), so Pass band width is 770 nm. It is clearly shown that centre band gap lie is at 1600 nm (Approx) but
our working wavelength is 1550 nm. For this reason wavelength shifts towards the higher frequency range with
respect to corresponding wavelength (λ0). Starts from 1870 nm (Approx) here find another Pass band till
investigate of our range 2400 nm.
Fig8: Plot between
Wavelength(nm) Vs. Transmission Coefficient in case of Silicon Carbide_Silica based photonic crystal
containing number of unit cells (N) = 20
V. Conclusion
From the below , combinations of different 2 layers photonic crystal(shown in table) it is become easier
to compare the various characteristics and from below table it is clearly shown that for different material
combinations the characteristics of SiC based photonic crystal has been varying. In case of stop band there is a
large variation but in pass band the variation is not so large as of stop band .In this Silicon Carbide based 1D
photonic crystal with 2 layered unit cell there are particular two types of semiconductor material combinations
where selectivity of that two unit cell are not so good that’s why firstly impossible to get stop band, after
increasing the number of unit cell the selectivity will stand in a good position and then stop band is clearly
shown.
7. Characteristics analysis of silicon carbide based 1-D
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Material
Stop band
width (nm)
approx.
Pass band width
(nm) approx.
Centre band gap
(nm) approx.
Deviation of
wavelength
w.r.t. 1550 nm.
Silicon_Silica 850 700 1680 130
Silicon_Silicon Carbide 320 840 1580 30
Silicon Carbide_Air 950 680 1680 130
Silicon Carbide_ Silica 550 770 1600 50
References
[1] J. D. Joannopoulos, S. G. Johnson, J. N. Winn, R. D. Meade, “Photonic Crystals Molding the Flow of Light”, Princeton University
Press, 2008.
[2] J. W. Haus, “Photonic Band gap Structures” in nanometer structures: Theory, Modelling and Simulation (Ed: A. Lakhtakia), PHI, New
Delhi, 2007, P. 45.
[3] “Photonic crystal”, http://en.wikipedia.org/wiki/Photonic_crystal