An Introduction to Laser Technology and Its Applications

1 An Introduction to LaserTechnology and Its Applications2018 2019 SCIENCER esource GuideThe vision of the United States Academic Decathlon is to provide all students the opportunity to excel academically through team competition. Toll Free: 866-511-USAD (8723) Direct: 712-326-9589 Fax: 651-389-9144 Email: Website: material may not be reproduced or transmitted, in whole or in part, by any means, including but not limited to photocopy, print, electronic, or internet display (public or private sites) or downloading, without prior written permission from USAD. Violators may be prosecuted. Copyright 2018 by United States Academic Decathlon.

2 All rights Pa. Collegiate Academy - Erie, PA2018 2019 Science Resource Guide2 Introduction ..4 SECTION I: LIGHT ..5 Introduction .. 5 Properties of Light .. 5 Waves ..5 Wave Properties ..5 Electromagnetic Waves ..6 The Speed of Light ..8 The Electromagnetic and Radio vs. Opaque Materials ..11 Visible Light and Color .. 12 The Visible Absorption and Reflection ..13 Selective Transmission ..14 Blue Skies and Red Sunsets ..14 Section I Summary ..16 SECTION II: OPTICS ..17 Introduction .. 17 Geometric Optics .. 17 The Ray Approximation .. The Law of Specular and Diffuse Reflection .. The Law of Refraction ..19 Mirages.

3 20 Dispersion ..21 Rainbows ..21 Total Internal Reflection ..22 Fiber-Optics ..23 Mirrors and Lenses ..23 Plane and Convex Mirrors ..25 Concave Mirrors ..25 Convex Mirrors .. Converging Diverging Lenses ..29 Spherical and Chromatic Principle ..30 Diffraction .. Double Slit Diffraction Thin-Film Interference .. Magnifier ..37 Microscopes .. II III: .. 41 Light Emission and of ContentsNorthwest Pa. Collegiate Academy - Erie, PA2018 2019 Science Resource Guide3 The Atom ..42 The Bohr Model ..44 Atomic Excitation and Emission ..45 Emission ..48 Absorption ..51 Phosphorescence.

4 Incandescent Fluorescent Lamps and Light-Emitting Operation ..55 Stimulated Emission ..56 Population Energy Levels ..58 Optical Cavity ..59 Properties of Laser Light ..59 Monochromatic ..60 Directional ..60 of Lasers ..60 Gas Lasers ..60 Solid-State Lasers ..61 Semiconductor Diode of the 50: Early Foundations ..62 Early 1950s: Charles Townes and the 1950s: Laser : The Race to Build the Laser ..641970s Present ..64 Section III Summary .. 65 SECTION IV: Applications OF LASERS ..67 Introduction .. 67 Scientific Laser Scanning Microscopy ..67 Manipulating Tiny Optical Laser Atomic Clocks.

5 71 Nuclear Fusion ..71 Medical Applications .. 73 Laser Surgery ..73 Refractive Eye Surgery ..75 Laser Dermatology ..76 Laser Applications .. 78 Laser Drilling ..78 Laser Cutting ..78 Laser Beam Marking, Engraving, and Etching .. Applications ..81 Barcode Readers ..81 Laser Printers ..82 Optical Discs: CDs, DVDs, and Others .. IV Summary ..94 BIBLIOGRAPHY ..95 Northwest Pa. Collegiate Academy - Erie, PA2018 2019 Science Resource Guide4 IntroductionThe Laser is among the most important inventions of the twentieth century. Since its Introduction in 1960, the Laser has made possible a countless number of scientific, medical, industrial, and commercial Applications .

6 Theodore Maiman, the inventor of the first working Laser , was quoted by The New York Times in 1964 as calling the Laser a solution seeking a problem. Today it s nearly impossible to go an entire day without using at least one object that was either manufactured using lasers or that uses lasers in order to function. In this Science Resource Guide, we will explore the nature of light and optics, the basic operation of a Laser , and the various Applications of lasers that have transformed our lives over the course of more than half a century. Along the way, we will consider significant milestones in the development of the Laser , as well as the people who contributed to our understanding of both lasers and light itself.

7 You ll also have opportunities to explore light-related phenomena using online simulations and simple demonstrations with everyday I will cover the basic properties of light as an electromagnetic wave. In this section, we will discuss how visible light represents a relatively small segment of the complete electromagnetic spectrum. We will also explore how the colors that we see are caused by interactions between visible light and Section II, we will consider the field of optics, which concerns the behavior of light, the formation of images, and the phenomena of reflection, refraction, and diffraction. As we will see, lenses and mirrors can be configured to focus light in particular ways, which will become important in understanding Laser operation and III will provide an overview of the Laser itself.

8 We will start by considering how light emission can be explained using a quantum model of atomic excitation, and explore various mechanisms of light emission. By the end of this section, you will be familiar with the most important properties of Laser light, the main categories of lasers, and the history behind the development of the , Section IV will provide an overview of major Applications of lasers across several categories. Lasers are an important tool in a variety of research fields, and they have also made possible new surgical procedures and manufacturing techniques. Lasers are all around us, in Laser pointers, Laser printers, and optical disc readers.

9 By the end of this guide, you will be able to explain how lasers work and the significant ways in which they contribute to our daily TO STUDENTS: You will notice as you read through the Resource Guide that some key terms and phrases are boldfaced. These terms are included in the glossary at the end of the Resource Pa. Collegiate Academy - Erie, PA2018 2019 Science Resource Guide5 Section ILightINTRODUCTIONL ight is both a familiar and fascinating phenomenon. Although a Laser beam and a flashlight beam have very different properties, they are still governed by the same fundamental principles that describe light. In this section, we will set the stage for our discussion of the Laser by covering some of the most fundamental properties of light and OF LIGHTWAVESMany phenomena in the known universe are described by the general mathematical concept of waves.

10 For example, the beam of light produced by a Laser , the sound generated by a thunderclap, and the ripples of water in a pond are all waves. A wave is the motion of a disturbance between two points. You ve likely observed how dropping a small object, such as a pebble, into a pond causes ripples of water to spread outward from where the object lands. The pebble disturbs the water immediately surrounding it, which disturbs the water further out, which disturbs the water further out, and so on (Figure 1).Waves can be classified as transverse or longitudinal. A transverse wave is made up of oscillations that are perpendicular to the direction that the wave travels.