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Lasers, Holography and Photonics Primer: Here is a great PDF student study guide that you can read and / or download to help with your understanding of lasers, optics, and holography. It also contains history and bios of some of the early researchers in the field. You may use it for homework assignments. Please give credit to holoworld.
Basic Laser Principles: Lasers are devices that produce intense beams of light which are monochromatic, coherent, and highly collimated. This download will provide information on how lasers make the special light that we've come to know as "laser light". Educational document produced by Melles Griot. Download file size: 270k.
Types of Lasers: There are several different types of lasers that you need to know about. This download will provide information on the how and the why different lasers produces different types of light. Educational document produced by Melles Griot. Download file size: 242k.
Lasers and their Applications: Lasers are all around us ... although they work primarily in the background. This document explains the many different applications of lasers in today's modern 21st century. Is there a laser in YOUR future? Educational document produced by Melles Griot. Download file size: 131k.
What are lasers used for?Hello. My name is Frank DeFreitas and I saw my first laser beam in 1968 (I was in the 8th grade). If you'd like to learn about how lasers are used today, you've come to the right web page!
Laser light is made up of only one color of light concentrated into a narrow band of frequencies. This property is called monochromaticity. Laser light also has directionality; that is, it concentrates in a narrow beam and travels in one direction. A third characteristic is coherence. The waves of a laser travel in step with one another like the members of a marching band. The force created by all the members putting a foot down at the same time is much stronger than random steps at different times. Likewise, the force of the signal or pulse from the coherent beam of light is more powerful than that of any single wave.
These properties make lasers useful in many ways. The directionality of laser light allows it to travel great distances and remain intense. It can be focused to drill holes or weld metal. The monochromaticity of laser light makes it useful in the analysis of chemicals based on the patterns of light each element absorbs. The coherence of laser light makes it useful in measuring distances with extreme accuracy in surveying, missile tracking, and in creating three-dimensional photography (holography).
Lasers consist of four components. (1) An active medium that can be solid, liquid, or gas. (2) An excitation medium that is a source of energy such as an electric current or a flash of light that excites or stimulates the active medium so that it produces light. (3) The feedback mechanism, usually two carefully aligned mirrors, lets the light bounce back and forth again and again through the active medium so the light is amplified. (4) An output coupler, one of the feedback mirrors that lets some of the light escape from the active medium. The light that escapes is the laser output. This output can be either a steady beam or bursts of light.
Today, hundreds of lasers serve in thousands of ways. In medicine, they can destroy some cancer cells, seal detached retinas in the human eye, and perform bloodless and reconstructive surgery. In telecommunications they transmit millions of television channels and provide secure communications systems. They act as range finders or survey instruments. They can measure vast distances, and track and dock spaceships. Lasers can guide gigantic machines that bore tunnels in hard rock. They may check the motion of the earth crust. They can cut, drill, and weld metals. Lasers make it possible to create holograms, or three-dimensional images. Holograms on charge cards and identification cards make them less easy to forge. Holography gives clear underwater pictures and lets pilots see their instruments without looking down at them. Holography lets physicians view broken bones, human organs, and the back of the eye.
Laser technicians produce and work with lasers. Laser test technicians test lasers. Holographic technicians make holograms. Since many of their duties are similar, the term technician in this brief applies to all three workers.
Technicians work under the guidance of scientists or engineers who do research and develop or design lasers and laser applications. These technicians may work alone or as members of a team to use, test, repair, and maintain different kinds of lasers and the systems that use them.
To build a solid-state laser, laser technicians first rotate a small crystal in a heated chemical mixture. The mixture builds up on the crystal layer by layer to form a rod. The rod, cut and polished, serves as the crystal for the laser. Usually the people who make the laser buy the rod. It is rare for the same technician to grow the crystal and make the rod.
Next, the laser technicians put a flash tube next to the crystal. They put the unit in a reflective coated container with a mirror at each end. They position each mirror at each end. They position each mirror with precision instruments so that all emitted or reflected light will pass through the crystal.
They put the laser body in a chassis and install tubing and wiring to the controls. They place a jacket around the assembly. (Water to cool the laser will flow through this jacket.
Technicians troubleshoot and repair laser systems and electro-optical devices. To conduct tests, they use instruments like oscilloscopes and streak cameras. They align laser-related optical systems and operate laser systems
Technicians process photographic film and plates. They make, reconstruct, and record holograms.
Technicians in the optical fiber communications industry use lasers to send messages. They develop, make, and test products. They may use computers to design, set up, monitor, and maintain fiber fabrication.
Technicians work on military and space projects. They repair and adapt low-power lasers used in target tracking, ranging, identification, and communications.
Laser holography is useful in the nondestructive testing of parts. Holograms can reveal flaws in items ranging from tiny crystals to huge machines. Technicians conduct these tests.
Technicians may also design, build, use, maintain, and repair lasers in research laboratories. They carry out similar tasks in research and development and in data storage. In photo optics, technicians service lasers used in high-speed photography and mapping. In construction and mining, technicians work with lasers in surveying , measuring, testing, and alignment. In the entertainment field they set up and maintain the lasers that make designs and produce color effects.
Technicians may build production and test stations that have lasers. They may follow drawings and work under the direction of an engineer.
Many laser technicians work as field service representatives, installing lasers at customer sites, making final adjustments, and demonstrating their use.
All technicians keep careful records. They make and read shop drawing and sketches. They keep laboratory notebooks, gather data, and make reports.
1970 Laser History: This system, developed by IBM's Systems Development division, enables scientists to compress information equal to 10,000 typewritten pages into a three-inch square hologram -- a photographic negative capable of displaying images in three dimensions. When a laser beam is projected through the hologram (as shown) it transmits the stored information to a light-sensitive detector that converts the images into electrical signals that can be read by a computer.
(Original photograph owned by the Frank DeFreitas Laser & Holography Archive. May be used for educational purposes with credit line.)
Laser technicians serve in laboratories and hospitals and sometimes in manufacturing plants. Some build and use lasers in the same place every day. Others move about often, in and out of laboratories, construction sites, or offices. Some technicians work in one office or laboratory and do not travel. Others, especially those in sales or services jobs, may travel.
Most work sites are heated, air-conditioned, and free from noise. Technicians that work on sensitive equipment work in clean rooms, in which the temperature, humidity, and dust content are carefully controlled. Other places, such as production lines and construction projects, may be busy and noisy. Technicians in construction may wear hard hats and other safety gear.
Working with lasers has its dangers. The electrical equipment associated with a laser could kill a careless user. Since laser beams can cause severe injury to the eye, workers must wear safety goggles when working with high-powered lasers. Technicians must be especially careful when working with lasers that emit an invisible beam. They must be aware of dye solutions, gas-filled discharge tubes, and high-voltage power sources.
Education and Training
Laser technicians need a broad base of electrical, electronic, mechanical, and optical skills. High school courses should include algebra, geometry, trigonometry, and English. Students should have at least one year of a physical science such as physics. Helpful also are chemistry, drafting, computer programming, vocational machine shop, blueprint reading, and basic electronics.
Technicians must have study and training beyond high school. Interested individuals can earn a bachelor's degree in laser and optical technology. Another option is to attend a two-year college or technical school and earn an associate degree for completion of a program in laser principles and photonics technology. Vocational schools also offer studies in this field. Students may spend more time in the laboratory or on work projects than in the classroom.
The first year in a program for technicians may include mathematics, physics, drafting, and diagramming and sketching. Other useful studies are basic electronics, industrial safety, electronic instrumentation, and electromechanical controls. Students may also take introduction to lasers, machine tools and shop practices, and introductory computer programming. Optics is an important part of the curriculum.
The second year of study may include solid-state circuit analysis, digital circuits, microwaves, and laser and electro-optical components. Students may also study laser and electro-optic measurements, laser applications, laser materials, and wave optics. Students may take glassblowing and vacuum techniques, communications skills, technical report writing, and microcomputers and computer hardware.
Students may take part in laser projects in their second year. These activities teach them more about work on their own. Some employers offer on-the-job training for the technicians they hire.
Laser technicians must be prepared to study continually in order to keep up with advances in this new field. Photonics technology is fast-changing, and new applications require new techniques.
Did You Know? ...
1961 Laser History: Did you know that the LASER was first called an "Optical MASER" when it was first conceived and invented? Click on the photo shown above to see the rest of the story. (Original photograph and/or negative owned by the Frank DeFreitas Laser & Holography Archive. May be used for educational purposes with credit line.)
Credentials, Organizations, and Unions
Most laser, test, and holographic technicians need not be ceritifed or licensed. As a rule, they do not belong to a union. In some government or military jobs several groups promote the interests of these workers. Among them are the Laser Institute of America and the Optical Society of America. SPIE-International Society for Optical Engineering is a major society for laser professionals. It has 14,000 members. The Lasers and Electro-Optics Society, a subsidiary of the Institute of Electrical and Electronics Engineers for laser professionals, publishes journals in the field.
Laser, test, and holographic technicians should have problem-solving skills. They must be able to understand and follow directions exactly. They should enjoy and be able to do detailed work and to make delicate adjustments. They should be able to work well both alone and with others. These technicians must be able to take responsibility
Occupations can be adapted for workers with disabilities. Persons should contact their school employment counselors, their state department of vocational rehabilitation, or their state department of labor to explore fully their individual needs and requirements as well as the requirements of the occupation.
Technicians work in industry, in research laboratories in hospitals, and on construction sites. They work for the government and the military. They work in cities, in suburbs, and in remote places. They may work a test range in the desert, survey the shores of an ocean, or service a telescope on a mountaintop. More than 80 percent of the laser technicians are employed in the urban regions of California, Florida, Massachusetts, New Jersey, Washington, D.C., and New Mexico.
The demand for skilled, experienced technicians exceeds the supply. Due to the ever-increasing number of uses for laser technology, market surveys show that the laser industry is now growing at the same rate as the computer industry did a few years ago.
The use of lasers in medicine, telecommunications, manufacturing, construction, data storage and retrieval, and photography, and scientific research and development insures a continued demand for technicians. Funding cutbacks in space technology are curtailing hiring in this field, however. Enlistment in the Armed Forces may lead to a career in laser technology. Defense industries are another field in which the demand for technicians has lessened.
Source: United States Department of Labor Statistics.
So, let's get right to the l-o-n-g list of what lasers are used for. You have my permission to print out this list for reports and homework.
If you're an educator, you may wish to assign several of the listed uses to students, and have them report on how lasers are used with them.
Note: I'm certain that this list is not complete, and it will always continue to grow. If you know of yet another use of lasers (to add to the list), please contact me and I'll make sure it gets posted in a future update.
What Lasers are Used For:
Repairing detached retinas * Reading product codes on groceries * Recording and playing CDs & DVDs * Cutting fabric for clothes * Drilling holes in metal * Inspecting bottles * Transmitting telephone calls and data * Surveying roads * Sounding the atmosphere * Dazzling concertgoers * Annealing microcircuits * Welding metal * Characterizing surface roughness * Measuring air pollution * Fingerprinting diamonds * Defining the meter * Slowing atomic beams * Printing computer data * Measuring the earth-moon distance * Cutting airplane parts * Transmitting news wirephotos * Aligning precision machinery * Making Holograms * Controlling tunnel machinery * Configuring massive telescopes * Designating military targets * Diagnosing flames * Leveling land * Controlling inventory * Analyzing compounds * Finding impurities * Aligning sawmill cuts * Monitoring polar ice caps * Measuring airplane velocity * Cleaning teeth * Looking for gravitational radiation * Installing acoustical ceilings * Read / write data storage * Identifying molecules * Aiding robotic vision * Inspecting tires * Positioning medical patients * Probing genetic material * Inspecting textiles * Removing birthmarks * Illuminating fluid flow * Communicating underwater * Enlarging color photographs * Teaching optics * Identifying viruses * Creating laser light art * Sensing rotation * Performing microsurgery * Erasing ink * Powering optical computers * Trimming resistors * Altering interconnects * Analyzing materials * Cleaning diamonds * Analyzing auto exhaust * Orienting crystals * Aligning jigs * Ranging targets * Watching continents drift * Sizing atmospheric dust particles * Cleaning art relics * Tracing air currents * Measuring molecular density * Imploding microfusion pellets * Sensing cloud altitude * Monitoring earthquakes * Gauging fine wines * Testing optical components * Analyzing thin film compositions * Drilling holes in diamond dies * Testing relativity * Separating isotopes * Sensing liquid level * Sensing magnetic fields * Programming read-only memory * Counting blood cells * Guiding missiles * Gauging film thickness * Monitoring crystal growth * Aligning large optics * Shaping jewel bearings * Measuring the speed of light * Securing perimeters * Positioning x-y stages * Computing in parallel * Pumping hard-to-pump lasers * Astonishing moviegoers (special effects) * Creating highly excited atoms * Amplifying images * Cauterizing blood vessels * Diagnosing fusion plasmas * Enhancing chemical reactions * Engraving identification marks * Hardening surfaces * Perforating computer paper * Producing advertisements *
-- Frank DeFreitas