This Spectra-Physics model 1077 "Level-Eye" laser light detector was made in the early 1980s. After setting-up a laser-emitter a construction worker could use this detector to take readings and check for level on a job site. The unit has both a visual display and an audible tone to tell the worker when the detector is centered on the signal. It has two accuracy settings, plus or minus 1/8 of an inch or 1/16 of an inch.
The term “home-made laser” almost seems a contradiction but that is not the case. This gas laser was built by high school student Stephen M. Fry in 1964, only four years after Ali Javan made the first gas laser at Bell Labs. Fry followed plans published in Scientific American's "The Amateur Scientist" column in September 1964, (page 227).
The glass tube is filled with helium and neon and, as the magazine reported, "seems to consist merely of a gas-discharge tube that looks much like the letter 'I' in a neon sign; at the ends of the tube are flat windows that face a pair of small mirrors. Yet when power is applied, the device emits as many as six separate beams of intense light."
The discharge tube is the only piece of this particular laser that remains. The flat windows (called "Brewster windows") are square instead of round, and the electrodes are parallel to the gas tube instead of perpendicular. Otherwise it resembles the drawings in the magazine. Fry later earned a Ph.D. in physics with a dissertation on lasers.
This is an experimental ruby laser made in 1963 at Ohio State University. Edward Damon, a researcher at the University’s Antenna Laboratory, made this and several other lasers during his investigation of Theodore Maiman’s ruby laser experiments of three years earlier.
In addition to replicating Maiman's 1960 experiments, Damon wished to explore variations of the ruby laser. Unlike Maiman's laser, this laser does not use a spiral flashlamp to energize the ruby crystal. Instead, Damon placed three linear flashlamps parallel to the rod-shaped laser crystal. Firing these lamps simultaneously provided energy to the crystal. The laser also demonstrates a water cooling technique still used in some lasers today.
Ralph Burnham and Nick Djeu made this prototype excimer laser in mid-1975 while at the Naval Research Laboratory. A modified carbon-dioxide laser known as a TEA laser (Transversely Excited, Atmospheric pressure), this laser used a mixture of xenon and fluoride gasses to produce a pulse of ultraviolet laser light. Ultraviolet light has a shorter wavelength than visible light and thus a higher energy level.
The term "excimer" refers to a molecule of two identical atoms that remains stable when in an excited state. The first laser to use such molecules was made in Moscow in 1970 and used molecules consisting of two xenon atoms. Lasers using molecules of differing atoms (technically called an exciplex-laser) were made by several teams of researchers in the US early in 1975. Burnham and Djeu's breakthrough lay in using a commercially available TEA laser to generate the excimer laser pulse. Their apparatus was much smaller and used less energy than prior excimer lasers that were energized by electron-beams.
This is an experimental ruby laser made in 1963 at Ohio State University. Edward Damon, a researcher at the University’s Antenna Laboratory, made this and several other lasers during his investigation of Theodore Maiman’s successful ruby laser experiments of three years earlier.
An important part of science consists of replicating the experiments conducted by other researchers and confirming their results. Like Maiman's 1960 laser, Damon's 1963 laser used a photographer's helical flashlamp to energize the ruby crystal. It demonstrated the use of mirrors external to the ruby rod instead of mirrors deposited in the crystal itself. The mirrors are on adjustable mounts that allowed Damon to make a variety of experiments with this unit.
This laser eraser was made and used by physicist Art Schawlow while at Stanford University. If he made a mistake while typing, Schawlaw could simply press a button and vaporize the typewriter ink, thus removing the incorrect characters. The wavelength of the laser was optimized for the absorption characteristics of the ink. Only the ink, not the paper, went up in smoke. Though the eraser was too expensive for commercial production, Schawlow received US Patent 3,553,421 for the invention and used the eraser on his office typewriter.
The object includes a power supply (to convert alternating current of 120 volts to 900 volt direct current pulses), the laser emitter, a connecting cable and carrying case.
Potential military uses for lasers have attracted both government funding and popular interest. While laser ”ray guns” remain in the realm of science fiction, significant research has been conducted toward that goal. In the 1980s, tests of a deuterium-fluoride (or DF) chemical laser were conducted at the U.S. Army's Redstone Arsenal. A chemical reaction created the energy necessary to generate a laser beam. As this object shows, that beam can be quite powerful.
In 1985, the Army transferred this test target to the Smithsonian. The target consists of six steel plates, each about 2 mm thick, bolted together. A hole of decreasing diameter is burned through the target from front to back. Information provided with the target reported that a 130 kilowatt laser illuminated the target from a distance of 60 meters for 5 seconds.
This is one section of a laser amplifier tube from the Shiva experimental fusion apparatus, operated at Lawrence Livermore National Laboratory from 1978 through 1981. Scientists used the Shiva device to test theories about how lasers might be used to trigger a nuclear fusion reaction. The research program was part of the continuing quest to harness nuclear fusion as a source of energy.
Lasers are useful in this type of research since they emit such a narrow beam of intense radiation. Shiva focused the energy of twenty laser beams on a tiny target of fuel to determine how the fuel would react. This amplifier tube is a short section of one of the twenty beam paths and contains panels of neodymium glass that strengthen and focus the light beam. Device included in Shiva laser chain, 1977-81. Power amplification - maximum 20. Donor notes: "These amplifiers were used in Shiva, a twenty-arm pulsed glass laser which preceded the Novette and Nova lasers."
Lasers have proven very useful in the construction industry. One example is this Spectra-Physics model 910 "LaserLevel" made in the early 1980s. In use, a construction worker attached the unit to a tripod and adjusted it so that it was nearly parallel to the ground. The level automatically completed the adjustment process when activated, and then emitted a beam of infrared light from a rotating head. The worker then moved to where-ever a measurement was needed and used a special laser detector to complete the task.
The "LaserLevel" self-adjusted if bumped slightly and completely shut off if bumped too much. The level operated automatically so it allowed one person to do work of two, resulting in cost savings since fewer assistants were needed.
As scientists and engineers came to better understand lasers, they developed a multitude of uses for this light source. The development of Compact Discs (CDs) and Digital Video Discs (DVDs) revolutionized the audio and video recording industries. Lasers are essential in making and playing both types of discs. Scientists refer to laser light as "highly coherent," meaning that the photons stay tightly focused rather than spreading out like the light from a flashlight. Coherent light can be focused on a very small spot. The pits on CDs and DVDs are microscopic.
This is the laser assembly from a Sony model D-5 "Discman" portable CD player. Donated in 1985, it shows how small lasers had become only 25 years after their invention. This object also shows the dramatic decrease in the amount of power needed to operate a laser. The power supply for Theodore Maiman's 1960 ruby laser is about 6 feet tall by 2 feet square and weights about 500 pounds. By contrast, the Sony "Discman" weighed less than 1 pound and operated on AA batteries.
A major breakthrough marks only the beginning of a scientist's work. In November 1960 Peter Sorokin and Mirek Stevenson, at IBM's Watson Research Center, successfully demonstrated a second type of laser. They energized a crystal of calcium-fluorine treated with a variety of uranium (written in chemical symbols as CaF2:U3+) to generate a pulse of laser light.
Sorokin and other colleagues experimented with many elements as they learned more about both pulsed and continuous-wave lasers. This crystal, from mid-1962, was the first one made of strontium, fluorine and samarium (SrF2:Sm2+) to successfully operate. Laser research was a very competitive field. Despite their efforts at IBM, Sorokin told museum staff that a team from Bell Labs, "made the first CW [continuous wave] solid-state laser using an ordinary crystal of CaF2:U3+. After that achievement we abandoned our CW efforts and went on to other topics." Those other topics included significant early work on generating laser beams using liquid dyes.
Scientists first made lasers using solid crystals or mixtures of gasses in 1960. Lasers using liquid dyes were developed in 1965. Dyes proved useful for making lasers that could be tuned over a range of light frequencies, somewhat similar to a musical instrument that can be tuned to different sound frequencies. Each of these five glass ampoules contains about 1 microgram of dye in a solution with 50 milliliters of ethyl alcohol. The glass ampoules are storage containers. In operation a dye is typically pumped through the laser apparatus.
These dye samples come from the Atomic Vapor Laser Isotope Separation Program (ALVIS) at Lawrence Berkeley National Laboratory. Light from a copper-vapor laser changed color (or frequency) by passing through a given dye, resulting in a laser beam with a specific frequency. Different frequencies equal different energy levels. Since atoms absorb energy at different frequencies, changing the laser light's color is a good way to impart just the right amount of energy needed to separate atoms such as isotopes that are almost, but not quite, identical.
This is a ruby crystal from Theodore Maiman's experiments of May 1960, and may be the first crystal to generate laser light. The synthetic crystal was mounted in a small holder that also contained a spiral flashlamp of the type photographers used. When the lamp flashed, the light pulse stimulated the atoms within the crystal. The atoms released that energy in the form of a laser light pulse.
Maiman earned a Ph.D. in physics from Stanford in 1955 and went to work at Hughes Research Laboratories the following year where he worked on masers. After attending a conference in September 1959, Maiman ran experiments investigating the possibility that a ruby crystal might be capable of emitting laser light. The experiments proved successful when, on 16 May 1960, he and assistant Irnee D’Haenes demonstrated the first operating laser. Rather than producing a continuous beam, their ruby laser operated in pulses. Their success caught the scientific community by surprise and was a pivotal moment in the history of lasers.
This crystal was one of several in the laboratory at the time of the experiments. No one knows with certainly which crystal actually generated the first laser light, though when the crystal was donated to the Smithsonian in 1967, officials at Hughes reported that this crystal was indeed the first.
This ruby crystal was used in early laser experiments at Bell Telephone Laboratories in Murray Hill, New Jersey. The first laser-related object in the Museum's Electricity Collections, it was acquired only three years after Theodore Maiman made the first laser at Hughes Aircraft in May 1960.
In May 1960 Theodore Maiman and Irnee D’Haenes, working at Hughes Aircraft in California, demonstrated the first working laser. The beam they generated was not continuous, however, but a rapid pulse of light.
This glass plate shows the spectral readings from Maiman's laser. The lines on this plate show that the laser did indeed function, and the wavelength of the light it emitted.
In 1957 Columbia University physicist Charles Townes discussed recent maser developments with Gordon Gould, a Ph.D. student at the University. Inspired by the conversation, Gould wrote down thoughts and ideas for lasers and had the pages of his notebook notarized. Recognizing the commercial potential of lasers, Gould left Columbia and pursued laser research at TRG, a defense company founded in 1953.
Though he lost the race to make the first working laser, Gould did make several lasers using cesium in 1961. This is the cesium light source for one of the early lasers based on his designs. The extent to which Gould’s notarized ideas were his own ignited fierce debate and patent litigation that lasted into the 1990s. The result of the litigation was that Gould’s patents, based on his 1957 notebook entries, were upheld.
A beam-type weapon, long familiar to science fiction fans, became a reality after the invention of lasers. That reality differed from fictional “ray guns” however. Rather than destroy a target directly, a solder used this battery-operated, portable laser to illuminate a selected target. A missile or other munition equipped with a special sensor detected the reflected light then homed-in on, and destroyed, the target.
This model AN/PAQ-1 laser target designator was developed at Hughes Aircraft Company following Theodore Maiman's creation of the first successful laser in May 1960. Before donating the laser to the museum in 1987, the U.S. Army removed a classified component so the laser will no longer function.
This carbon-dioxide gas laser was assembled and operated in 1979 by teenager Ebe Helm in the basement of his parent's New Jersey home. As Helm told museum staff, "The laser operated at 9000 volts, 120 milliamps, on alternating current. Because my gas supply was very limited, it functioned as a static, non-flowing gas laser. It did not function at the expected pressure of 4-10 torr, but only above 60 torr, well off the range of the vacuum gage I was using. The target is a building block donated from the nursery school that my mother operated from our home."
Mr. Helm donated this and other lasers to the Smithsonian in 2005.
The word laser stands for "light amplification by stimulated emission of radiation." A lasing material, a crystal for example, amplifies light energy fed into it from an external source such as a flash-lamp. Scientists and engineers refer to this as "pumping" the laser.
These objects are experimental discharge lamps used to pump a crystal of yttrium-aluminum-garnet that has been treated with neodymium. Dating from about 1967 these specialized discharge lamps are similar to high pressure sodium (HPS) lamps that are commonly used in street lights. They are unusual in that they are made with clear tubes of artificial sapphire. Corning Glass made the material, called "Corstar Sapphire," that was then used by Westinghouse to make lamps. The clear tube permitted more light to pass than the typical milky-white material used in ordinary HPS street lamps, increasing the energy fed into the laser crystal.
Lasers have served as teaching tools in more ways than one. This ruby laser, made by General Electric (GE), inspired teenager Ebe Helm from New Jersey to learn more about lasers.
Mr. Helm wrote: "this laser head was originally on display in the Franklin Institute in Philadelphia as part of an electromagnetic spectrum exhibit from GE. It was a working unit that would fire downward on a spool of typewriter ribbon when a button was pushed. The hole it burned could be observed from several angles around its display and through large magnifying lenses arranged over it. ... I first saw this laser on display during a class trip in 1972. The laser had been on display for some years, possibly since the 1960's, and was not working. After it had been removed to a basement store room I managed to talk the Franklin Institute into giving it to me in 1976. I used the components to make an operational ruby laser in 1977 at age 17."
Mr. Helm donated this laser, and several others, to the Smithsonian in 2005.