The document summarizes the history and operation of semiconductor diode lasers. It describes how the first laser diode was demonstrated in 1962 using gallium arsenide. It operates by stimulating electrons and holes to recombine and emit photons through forward biasing. There are several types of semiconductor lasers including homojunction and heterojunction lasers, which differ in their material makeup but operate on the principle of stimulated emission. Common applications include fiber optic communications, barcode readers, laser printers, and optical storage devices.
Introduction to semiconductor lasers, and its working. construction of semiconductor laser, Ga As laser, and construction, achievement of population inversion, pumping.
AĀ laserĀ is a device that emitsĀ lightĀ through a process ofĀ optical amplificationĀ based on theĀ stimulated emissionĀ ofĀ electromagnetic radiation. The term "laser" originated as anĀ acronymĀ for "light amplification by stimulated emission of radiation
Introduction to semiconductor lasers, and its working. construction of semiconductor laser, Ga As laser, and construction, achievement of population inversion, pumping.
AĀ laserĀ is a device that emitsĀ lightĀ through a process ofĀ optical amplificationĀ based on theĀ stimulated emissionĀ ofĀ electromagnetic radiation. The term "laser" originated as anĀ acronymĀ for "light amplification by stimulated emission of radiation
Laser is very important technological device these days.There is a use of laser in almost every field of science and technology. It also gives it's application in medicines also.
This presentation shows how it works and what is the mechanism behind this laser phenomenon. Here it is explained from atom theory to application.
Very good explanation with photographs.
Laser is very important technological device these days.There is a use of laser in almost every field of science and technology. It also gives it's application in medicines also.
This presentation shows how it works and what is the mechanism behind this laser phenomenon. Here it is explained from atom theory to application.
Very good explanation with photographs.
Optical fiber communication Part 2 Sources and DetectorsMadhumita Tamhane
Ā
For optical fiber communication, major light sources are hetero-junction-structured semiconductor laser diode and light emitting diodes. Heterojunction consists of two adjoining semiconductor materials with different bandgap energies. They have adequate power for wide range of applications. Detectors used are PiN diode and Avalanche Photodiode. Being very small in size and feeding to small core optical fiber, it is very important to study emission characteristics of sources and their coupling to fiber. As it can operate for low power over a long distance, received power is very small, hence study of noise characteristics of detectors is very essential...
A p-n junction diode which emits spontaneous emission of radiation in the visible and IR regions when forward biased is called Light Emitting Diode.
This converts the input electrical energy into optical energy in the visible or IR spectrum depending on the semiconductor material
Let's dive deeper into the world of ODC! Ricardo Alves (OutSystems) will join us to tell all about the new Data Fabric. After that, Sezen de Bruijn (OutSystems) will get into the details on how to best design a sturdy architecture within ODC.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Ā
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
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I have heard many times that architecture is not important for the front-end. Also, many times I have seen how developers implement features on the front-end just following the standard rules for a framework and think that this is enough to successfully launch the project, and then the project fails. How to prevent this and what approach to choose? I have launched dozens of complex projects and during the talk we will analyze which approaches have worked for me and which have not.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Ā
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Ā
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
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The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Ā
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
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In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Ā
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
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A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
Ā
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Ā
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Ā
Are you looking to streamline your workflows and boost your projectsā efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, youāre in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part āEssentials of Automationā series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Hereās what youāll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
Weāll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Donāt miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
From Siloed Products to Connected Ecosystem: Building a Sustainable and Scala...
Ā
Semiconductor laser
1.
2. ā¢ Semiconductor diode (the first laser diode) was
demonstrated in 1962 by two US groups led by Robert N.
Hall at the General Electric research center and by
Marshall Nathan at the IBM T.J. Watson Research Center
ā¢ The semiconductor laser is made in mass quantities from
wafers of gallium arsenide or similar crystals.
3. When the P-N Junction diode is Forward Biased (i.e) the P
end of the diode is connected to the positive terminal of the
battery and the N end is connected to the negative terminal
of the battery. The poles and electrons diffuse through the
junction and combine with each other; meanwhile light
radiations or photons are radiated. This is called
Recombination Radiation
These emitted photons stimulate Other electrons & holes to
recombine which Results in stimulated emission required for
Lasing Action.
5. Homojunction diode lasers are those in which P end and N end
of the diode are made of the same semiconductor material.
Example : Ga As laser
ā¢ They use Direct Band Gap Semi-
conductor material.
ā¢ P-N Junction act as the active
medium.
ā¢ The crystal is cut at a thickness of
0.5 mm
ā¢ Applied voltage is given through
metal contacts on both surfaces of
the diode.
ā¢ Pulse beam of laser of 8400 Ć is produced
6. FORWARD BIASED DIODE LASER
metal contact
Ga āAs material on both ends
P end
N end
Laser beam
+
8. Heterojunction Semiconductor lasers are those in which P end is
made of one type of semiconductor material and the N end is
made of another type of semiconductor material
Example : GaAIAs diode laser
ļ¶Use Direct Band Gap Semiconductor
ļ¶Consist of five layers namely
ā¢ GaAs ā p type
ā¢ GaAIAs ā p type
ā¢ GaAs ā p type (Active Medium)
ā¢ GaAIAs ā n type
ā¢ GaAs ā n type
ļ¶The end faces of the third layer is highly polished and perfectly
paralell to each other to reflect the laser beam ; one end is
partially polished to release the continious beam.
11. ā¢ Most SC lasers operate in 0.8 ā 0.9 Āµm or 1 ā 1.7 Āµm
spectral region
ā¢ Wavelength of emission determined by the band gap
ā¢ Different SC materials used for different spectral regions
ā¢ 0.8 ā 0.9 Āµm : Based on Gallium Arsenide
ā¢ 1 ā 1.7 Āµm : Based on Indium Phosphide (InP)
ā¢ Pumping method : Direct Conversion
ā¢ High power lasers usually (1 mV )
12. HOMOJUNCTION DIODE
LASER
ā¢ P and N regions are made
of the same diode
material
ā¢ Active medium : Single
crystal of PN Diode
ā¢ Pulse beam
ā¢ Wavelength : 8300Ć -
8500Ć
ā¢ Example : GaAs,InP.
HETEROJUNCTION DIODE
LASER
ā¢ P and N regions are made
of different diode material
ā¢ Active Medium : Third
layer of p type material
among the five layers
ā¢ Continuous beam
ā¢ Wavelength : 8400 Ć
ā¢ Example : GaAs/GaAIAs,
InP/InAIP .
13. ā¢ They are light weighted and portable.
ā¢ Battery supported ; easily replaceable
ā¢ Capability of direct modulation into Gigahertz region
ā¢ Small size and low cost
ā¢ Capability of Monolithic integration with electronic
circuitry
ā¢ Compatibility with optical fibres
14. ā¢ Due to relatively low power production, these lasers not
suited to typical laser applications
ā¢ The temperature affects greatly the output of the laser
ā¢ Beam divergence is much greater as compared to all
other lasers
ā¢ Cooling system required in some cases