What Are Lasers Used For?
** LIVE PRESENTATION **
Sunday, Apr 26, 2015 / 9:15 to 10:15 am
@ CHRIST EC CHURCH
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Updated 14 APR 2015
by Frank DeFreitas
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
Transmitting telephone calls and data
Sounding the atmosphere
Characterizing surface roughness
Measuring air pollution
Defining the meter
Slowing atomic beams
Printing computer data
Measuring the earth-moon distance
Cutting airplane parts
Transmitting news wirephotos
Aligning precision machinery
Controlling tunnel machinery
Configuring massive telescopes
Designating military targets
Aligning sawmill cuts
Monitoring polar ice caps
Measuring airplane velocity
Looking for gravitational radiation
Installing acoustical ceilings
Read / write data storage
Aiding robotic vision
Positioning medical patients
Probing genetic material
Illuminating fluid flow
Enlarging color photographs
Creating laser light art
Powering optical computers
Analyzing auto exhaust
Watching continents drift
Sizing atmospheric dust particles
Cleaning art relics
Tracing air currents
Measuring molecular density
Imploding microfusion pellets
Sensing cloud altitude
Gauging fine wines
Testing optical components
Analyzing thin film compositions
Drilling holes in diamond dies
Sensing liquid level
Sensing magnetic fields
Programming read-only memory
Counting blood cells
Gauging film thickness
Monitoring crystal growth
Aligning large optics
Shaping jewel bearings
Measuring the speed of light
Positioning x-y stages
Computing in parallel
Pumping hard-to-pump lasers
Astonishing moviegoers (special effects)
Creating highly excited atoms
Cauterizing blood vessels
Diagnosing fusion plasmas
Enhancing chemical reactions
Engraving identification marks
Perforating computer paper
-- Frank DeFreitas
"Science is the study of the physical manifestations of God in action."
-- Frank DeFreitas
Frank DeFreitas, holographer
Allentown, Pennsylvania, USA
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