CHAPTER 13 SEMICONDUCTOR LASERS Pamela L. Derry Luis Figueroa Chi-Shain Hong Boeing Defense & Space Group Seattle ‚ Washington 13.1 GLOSSARY A C c D Dc D d deff dG dg / dN E Ec Eg En E cn En E e Fc F fc fd fo fp Constant approximating the slope of gain versus current or carrier density Capacitance Speed of light Density of states for a transition Density of states for the conduction band Density of states for the valence band Active layer thickness Effective beam width in the transverse direction
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|LASER ALIGNMENT THEORY Modern optical metrology uses precise lines and planes in space from which measurements are made. Because this method creates these features using light it has become known as optical tooling. The 35 year old historical development and current technology of laser instrumentation as used in optical tooling is discussed in detail. This includes the how the measurements are made‚ applications‚ and the technology of alignment lasers and position sensing targets developed for
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Signature of Head of the Institution with seal Date: Place: LASERS AND ITS APPLICATIONS Abstract: A laser is an optical device that emits coherent light (electromagnetic radiation). The term ’laser’ is an acronym for Light Amplification by Stimulated Emission of Radiation. Typically‚ lasers are thought of as emitting light in a narrow‚ low-divergence beam‚ with a narrow wavelength spectrum (’monochromatic’ light). Lasers need not have either characteristic‚ however‚ it is the coherence of
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What is laser retinal detachment surgery? How does the lasers work? What is retinal detachment? In the early 1970’s‚ laser were first used to treat eye diseases and has since then become the standard practise for formerly untreatable disorders. Even when there is haemorrhaging and leakage in the back of your eye‚ almost always‚ the eye will look and feel normal when suffering from retinal diseases. Therefore‚ the only way to conclude the necessity of laser surgery is to have a careful‚ dilated retinal
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played with lasers? We have all loved the laser fights in movies like Star Wars. Who wouldn’t want wield a laser around while fighting an enemy. Did you know that the term laser came from an acronym meaning “light amplification by stimulated emission of radiation.”? It should actually be all capitalized but for simplicity it isn’t. The first working laser was actually demonstrated by Theodore Maiman at the Hughes Research Laboratories back in 1960. The strength of early lasers was measured
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While both laser therapy and scaling and root planing are both effective treatment methods for periodontal disease‚ scaling and root planing is used as a traditional method also called a deep cleaning while laser therapy is used as a relatively new alternative therapy. Both methods are usually used for patients who have periodontal disease with gingival pocket depths over 4mm. Though scaling and root planing has been the conventional treatment in the past‚ since 2008 laser therapy has doubled in
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LASER COMMUNICATION SYSTEM Naveen IV Sem‚Dept of Electronics & Communications Sahyadri College of Engineering & Management‚Mangalore ABSTRACT: Laser communication is one of the key area in wireless Communications. This paper includes analysis‚ optimization‚ design and system level development of signal transformation between satellites or any two sources. Which work similarly to fiber optic links‚ except the beam is transmitted through free space. While the transmitter and receiver must
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The ruby laser‚ first invented in 1960‚ was the world’s first laser. Created by Theodore Maiman‚ the ruby laser is composed of aluminium oxide where some of the aluminium ions have been replaced with chromium ions. These chromium ions are what gives the ruby laser its red color. Its gain medium is a cylindrical crystal. A fully reflecting mirror and a partially reflecting mirror are placed at both ends of the cylindrical crystal. A high intensity lamp is spiraled around the cylinder to produce a
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separate eyes creating two separate images‚ while the ability to adapt to light change is attributed to the iris and the dilator muscles. However these two aspects of the eye are not involved in laser eye surgery and will not be discussed in reference. The focusing of objects and images is very much part of laser eye surgery. In order for a clear visual image to be formed the image must come to a point on the retina. Light rays do not normally travel toward each other‚ usually the light rays either travel
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The name LASER is an acronym for Light Amplification by the Stimulated Emission of Radiation. In 1917‚ Albert Einstein first theorized about the process which makes lasers possible called "Stimulated Emission." In this paper‚ we can view the impact of the lasers technology on society from four perspectives: the strength‚ the weakness‚ the opportunity and the threat of Lasers Applications. To sum up‚ we will focus on the future of Lasers on society‚ assessing the real value of the Lasers technology
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