Coherent Laser Diode

Physics Question (10 Points)?

a) In a diode laser, electrons dropping from the conduction band, across the gap, and into the valence band produce the photons that add to the coherent light. The ZnTe laser has a band gap of 2.25 eV. Determine the wavelength of the light emitted.

b) The energy gap for Si at 300 K is 1.14 eV.
i) Find the lowest-frequency photon that will promote an electron from the valence band to the conduction band of silicon.

ii) What is the wavelength of this photon?

c) Near room temperature, an increase of I K decreases the conductivity of copper by only 0.4%. For another semiconductor, it increases the conductivity by 4.8%. Estimate the semiconductor’s band gap.

answers for b and c are
b i) 2.75 X 1014 Hz ii) 1.09 X 10-6 m c) EGAP = 0.68 eV
but I dont know how to get there

a) The relation between photon wavelength and energy is E = hc/lambda, where h = Planck's constant, c = speed of light, lambda = wavelength

Just plug in the numbers. Since E is in eV, you can use h in eV units, which is 4.14 x 10^-15 eV-s

If c is in m/sec, the wavelength will be in meters.

b) i) Instead of E = hc/lambda, use E = hf. Just plug in the values of E and h.

ii) Now you can use f = c/lambda to solve for lambda

c) I would guess there is a formula in your notes that says "relationship between conductivity temperature" that is the key to this problem.

Laser Diode Microsystems (Paperback) $99.13 Description not available.

CET Domain 10021910 Playstation 3 Compatible Laser Diode $72.83 Replace your damaged laser diode built for Playstation 3 KEM400AAA and KES400AAA laser lenses. Use and replace your laser diode with precaution. All laser diodes are extremely ESD sensitive. Compatible Models: Playstation 3 compatible KEM400AAA and KES400AAA laser lenses (sold seperately). Note: Installation guide is not included please look for it online or use the help of an accreditate technician. We will not be responsible for any damage of your device due to improper installation.

Cet 10021911 Playstation 3 Compatible 410 Series Laser Diode $46.28 Replace your damaged laser diode built in your PlayStation 3 KEM410 and KES410 laser lens. Use and replace your it with precaution as this laser diode is very fragile and extremely ESD sensitive. Compatible Models: Playstation 3 compatible KEM410 and KES410 laser lenses (not included). Note: Installation guide is not included please look for it online or use the help of an accreditate technician. We will not be responsible for any damage of your device due to improper installation.

Wasp Barcode Technologies LS 2208 - Barcode Scanner- Single-Pass - 100 Scan / Sec - Visible Laser Diode $144.6 Wasp Barcode Technologies LS2208-1AZK0100S LS 2208 - Barcode Scanner- Single-Pass - 100 Scan / Sec - Visible Laser Diode

Mid-infrared Coherent Sources and Applications $74.1 This volume represents a collection of authoritative reviews by internationally recognized experts in the field of middle infrared (mid-IR) coherent sources and their applications. The compilation describes the fundamental principles and state-of-the-art of practical solid-state sources in the mid-IR regions of the spectrum covering the 2-50 m range. The described sources include, along with more traditional heterojunction semiconductor lasers, optical parametric oscillators, difference frequency generators, as well as the most recently developed broadband crystalline, quantum cascade and fiber lasers. The rapid advances in mid-IR science and technology have made these sources indispensable tools for a variety of applications in environmental monitoring and pollution control, agriculture and life sciences, and non-invasive disease diagnosis through breath analysis. Coherent mid-IR sources also offer important technologies for atmospheric chemistry, free-space communication, imaging, rapid detection of explosives, chemical and biological agents, narcotics, as well as for applications in air- and sea-borne security. In comparison to the previous volume on this subject in 2003, which focused mainly on the design and development of mid-IR sources, the emphasis in the present volume is shifted towards applications. The instructive nature of the book makes it an excellent text for practicing engineers, physicists and graduate students, who intend to develop or use mid-IR laser sources in various applications.

Coherent Control of Four-wave Mixing (Hardcover) $105.41 "Coherent Control of Four-Wave Mixing" discusses the frequency, temporal and spatial domain interplays of four-wave mixing (FWM) processes induced by atomic coherence in multi-level atomic systems. It covers topics in five major areas: the ultrafast FWM polarization beats due to interactions between multi-color laser beams and multi-level media; coexisting Raman-Rayleigh-Brillouin-enhanced polarization beats due to color-locking noisy field correlations; FWM processes with different kinds of dual-dressed schemes in ultra-thin, micrometer and long atomic cells; temporal and spatial interference between FWM and six-wave mixing (SWM) signals in multi-level electromagnetically induced transparency (EIT) media; spatial displacements and splitting of the probe and generated FWM beams, as well as the observations of gap soliton trains, vortex solitons, and stable multicomponent vector solitons in the FWM signals.The book is intended for scientists, researchers, advanced undergraduate and graduate students in Nonlinear Optics.Dr. Yanpeng Zhang is a professor and Zhiqiang Nie is a Ph. D. student at the Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi`an Jiaotong University, China. Dr. Min Xiao is a professor of physics at the University of Arkansas, Fayetteville, U.S.A.

Laser Stars Projector $169.99 Caution: This product is more amazing in real life than on a two dimensional website As you should well know here at ThinkGeek we are constantly striving to find tools for you, our loyal customers, to aid in your quest for World Domination. But we also want to encourage you to come up with schemes to conquer the entire Universe (and any parallel universes you might stumble across while conquering this one). And to properly conquer the known Universe, you'll need a a nice reliable star map. The Laser Stars Projector is not that map, but it sure does seem like one. And the second most important thing a Universe conqueror might do besides conquering Universes is seeming to conquer Universes. Keeps you buttered up for the real thing. Ok, carrying on then... When you turn off your lights and turn this unit on - trust us - you will be bamboozled with star rapture. That's the only way we can describe it. Everybody who has seen the Laser Stars Projector in action at the ThinkGeek headquarters has at least one 'Oh My Gods, that's Frakking brilliant!' moment. But ThinkGeek, what IS the Laser Stars Projector really? It's a unit about 10inches tall that projects a combination of green laser stars and blue (slightly ultraviolet-ish blue) clouds onto your ceiling, walls, pets, etc. Both the clouds and the stars are constantly moving and morphing, just like a proper Universe should. And there are literally thousands of green laser stars to look at. There are two ways you can adjust your Laser Stars Projector, first you can pivot the projector itself 180 degrees horizontally around the base so that you can control *where* it is projecting in your room. It can literally fill up an entire ceiling and portions of several walls at once. And the other thing you can adjust is the intensity of the blue gaseous clouds, from zero to full intensity. ThinkGeek, I'm a techie. How does it really work? The Laser Stars Projector utilizes a state of the art Diode Pumped, Solid State (DPSS) green laser combined with custom developed multiphase diffractive holographic optics, super luminous diodes and precision motors to produce the laser stars effect. The coherent light produced by the DPSS laser passes through a passive diffractive holographic optical element, which in turn passes through a circular periodicity electromechanical wheel, which is driven by a precision motor to create the soothing motion of the star field. So there. Hurry, get one before your friends do. Then plug it in, turn it on, and tune out... Features: Uses Green Laser and Holographic technology 2 built-in precision glass lenses Creates thousands of stars with or without blue cloud formations Ac Adapter Included (US Only - 120V) Unit Dimensions: 10" tall x 9" wide x 7" deep Please note: It's difficult to portray what the Laser Stars Projector projects here in images because it works best in the dark. The images tend to mute the green stars and exaggerate the blue clouds a bit. But we've tried our b...

DIODE $12.5 When these electrical items fail there is little choice but to renew - With this genuine Suzuki par..

International Symposium on Waves, Coherent Structures, and Turbulence in Plasmas (Hardcover) $91.09 The symposium covered a wide range of topics in the field of nonlinear phenomena in plasmas reflecting the enormous breadth of Prof. Kaw`s own research interests and included basic areas like turbulence, coherent wave interactions, quark gluon plasmas, dusty plasmas and applications to magnetic confinement fusion, laser fusion, space physics, and plasma processing. The proceedings volume contains a selection of the scientific presentations made at the conference by eminent experts in the field. The articles provide exciting accounts of many of the frontier areas of the field and collectively reveal the ubiquity and richness of nonlinear behavior in the plasmas medium.

Transistor-Diode Checker Kit $4.95 Transistor-Diode Checker Kit

American DJ Green Phantom Laser 889406634015 $100 Laser diode: 4.9mW, 532nm, Class III laser. Dimensions: 11.75"L x 9"W x 8"H. Weight: 4 lbs..

Diode Laser Materials and Devices : A Worldwide Market and Technology Overview to 2005 $2781.51 No Synopsis Available

Greatland Laser Rescue Laser Light $99.99 Greatland Laser Rescue Light . Signal for help, warn oncoming boats of your presence or locate your gear at night Signal other boats and aircraft in search and rescue emergencies, locate an overboard crewmember in the dark or find mooring balls and fishing gear. This compact nighttime signaling device is visible up to 20 miles away in optimal conditions, is effective in daytime up to 3 miles and locates reflective material up to one mile away. Features a long-life red laser diode that lasts up to 10,000 hours. Runs 40 hours on an easily replaceable 3-volt lithium CR123 battery. Machined aircraft aluminum anodized for corrosion resistance. Easy to carry on a keychain or in a pocket. Non-flammable, environmentally safe Rugged, machined aluminum with knurled design Long life laser diode - 10,000 hours meantime to failure Weighs 3.5 oz 3.125" long

CET Domain G0000003 5 Laser Heads Green Laser Pen Pointer $38.87 This laser pointer is the perfect item for pointing objects during screen presentations. Press one button and the Diode Pumped Solid State Frequency Doubled (DPSSFD) laser technology made of high grade components will do the rest. This laser points comes with 5 different heads that will change the shape of your laser.

Mackin Diode Light Pen, Pearl $10 Features of the Mackin Diode Light Pen: A quality pen with a diode flashlight.

OmniSistem Club Laser DMX Multicolor $649 Generates red, green, and yellow effects with a moving diode hits one of 8 aperatures.

OmniSistem Club Laser DMX Green $499 Generates red, green, and yellow effects with a moving diode hits one of 8 aperatures.

60 Watt Coherent Laser Diode Test

Laser Welding Ins and Outs You Don't Know

Laser welding plastics is a fairly new process. It super heats the polymer without physical contact. Most applications processes are done by, directing the beam of infrared light. Directly at the weld joint. This is done by going through one of the parts. Commonly referred to as, through transmission.

By directing infrared beam of infrared light at the weld joint via( a laser)welding. This technique, the infrared beam, usually a laser, irradiates the joint through a part and the light is absorbed at the surface of the other. While broad band infrared beams can be used, the monochromatic lasers allow very fast heating of small areas of the part that allows the parts to be welded very rapidly, but with very small changes to the geometry part.

Laser welding is a example of electromagnetic plastic welding process. Once radiant energy it has been directed towards polymer surface, a series of three things will happen to it, most of the light transmits through, some is absorbed, and some is reflected away. The application the process involves directing the beam of infrared light towards the weld joint through one of the parts. The part (laser) that transmits most of the energy will not heat, but the absorbing part will super heat .Most virgin, organic polymers will not absorb energy. Certain dyes and fillers such as carbon black are used. To absorb the energy at the weld joint interface. This is commonly called to as through transmission infrared (or laser) welding. Welding results when materials are heated to a molten state and fused together.

One type of material must transmit the laser light while the other absorbs it, While converting it to heat. The great news is that the materials must be transmissive. This all depends on formulation of the pigment. Joints that require optical clarity can be done by the use of special coatings types. Thermoplastics, Laser welding, resin compatibility , resin chemistry or melt temperature differences than most all other plastic welding processes these days.

Nd:YAG laser welding is used commercially, a wide range of C-Mn steels, stainless steels, coated steels, molybdenum, titanium, and aluminum alloys. Low heat input welding. These lasers is utilized in the electronics, domestic items, automotive sectors, the most interest has been shown more recently, to particularly for the high power CW lasers in the shipping industry. Oil and gas, R&D issues involving development of highly powered lasers of better beam quality, the use of distributed energy in the beam focus, maintenance for both thick and thin sections and weld classification.

Light energy is generated by lasers. That can be absorbed into materials and converted to heat energy. Laser emits coherent radiation. Lasers do minimal divergence that can travel over significant distances without loss of beam quality or energy.

Relatively new techniques in Laser welding have been compared to other plastic welding processes. Dedicated laser labs at EWI’s are equipped with lasers creating and analyzing plastics welding. The laser beam used to melt the base material and filler rod, this process becomes line of sight ,as well as focal point limited process. If you cannot get a straight shot, or you can't re-line the position of the weld area, it will not work efficiently or correctly. Microscopic magnification is also is used in the laser welding process.

The system is capable of welding materials that are galvannealed, electroplated or hot-dipped galvanized, that the coating thickness be both consistent on top of surface of the material, as well as controlled to 14 microns or less. The 3-kW diffusion-cooled slab laser used in the Utica system can be used to weld materials, ie mild steel, high-strength steel, stainless steel, aluminum. The biggest driving factor behind the development of laser welding is the fact that it makes the cans more esthetically attractive.

Beam delivery used optics that are mounted directly on the laser housing and fixed in focal length and beam position relative to the housing. Moveable part concept ,diode lasers mounted on robotics. Multiple-beam processing is new , relatively new field that has the potential. Enhancing the capabilities of high intensity laser and electron beam process.

Post heating, multiple-beam laser preheating is shown, first presented and analyzed. Followed by multiple-beam flow. this application electron beam welding. Other applications using laser machining and cladding. Particles with high melting points were distributed on the plate material in order to see the motions of these particles. And the enclosed motions of the melt pool during welding with different type of process gases. Photos show a change in the melt flow direction ,with active gas components towards the center of the pool and downwards towards the root side.

About the Author

Roger Hathaway from Arcor laser is experienced in laser welding and knows the difficulties that arise from meeting the demands of the 21st century manufacturing by utilizing the many benefits realized by laser materials processing.