This Day in Tech History

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From DVD’s to Yoda

0616yoda

March 22, 1960:   Schawlow & Townes Receive First Patent on a Laser

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term “laser” originated as an acronym for Light Amplification by Stimulated Emission of Radiation. The light emitted by many lasers can be made into a narrow beam or focused to a tight spot.

In 1957, Charles Hard Townes and Arthur Leonard Schawlow, then at Bell Labs, began a serious study of the infrared laser. As ideas developed, they abandoned infrared radiation to instead concentrate upon visible light. The concept originally was called an “optical maser”. In 1958, Bell Labs filed a patent application for their proposed optical maser; and Schawlow and Townes submitted a manuscript of their theoretical calculations to the Physical Review, published that year in Volume 112, Issue No. 6.

Charles Townes

Charles Townes

Arther Schawlow

Arther Schawlow

 

 

 

 

 

 

 

 

 

Simultaneously, at Columbia University, graduate student Gordon Gould was working on a doctoral thesis about the energy levels of excited thallium. In November 1957, Gould noted his ideas for a “laser”.  In the U.S., Schawlow and Townes had agreed to an open-resonator laser design – apparently unaware of Gould’s unpublished laser work.

GordonGould

Gordon Gould

At a conference in 1959, Gordon Gould published the term LASER in the paper The LASER, Light Amplification by Stimulated Emission of Radiation.

He continued developing the idea, and filed a patent application in April 1959. The U.S. Patent Office denied his application, and awarded a patent to Bell Labs, in 1960.

That provoked a twenty-eight-year lawsuit, featuring scientific prestige and money as the stakes. Gould won his first minor patent in 1977, yet it was not until 1987 that he won the first significant patent lawsuit victory, when a Federal judge ordered the U.S. Patent Office to issue patents to Gould for the optically pumped and the gas discharge laser devices. The question of just how to assign credit for inventing the laser remains unresolved by historians.

Gould_notebook_001

This is the first page of Gordon Gould’s famous notebook, in which he coined the acronym LASER, and described the essential elements for constructing one. This notebook was the focus of a thirty-year court battle for the patent rights to the laser. Notable is the notary’s stamp in the upper left corner of the page, dated November 13, 1957. This datestamp established Gould’s priority as the first to conceive many of the technologies described in the book.

Lasers have many important applications. They are used in common consumer devices such as DVD players, laser printers, and barcode scanners. They are used in medicine for laser surgery and various skin treatments, and in industry for cutting and welding materials. They are used in military and law enforcement devices for marking targets and measuring range and speed. Laser lighting displays use laser light as an entertainment medium. Lasers also have many important applications in scientific research.

How Lasers Work

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Many uses of lasers:

  • In science, lasers are used in many ways, including:
  • A wide variety of interferometric techniques
  • Raman spectroscopy
  • Laser induced breakdown spectroscopy
  • Atmospheric remote sensing
  • Investigating nonlinear optics phenomena
  • Holographic techniques employing lasers also contribute to a number of measurement techniques.
  • Laser based LIght Detection And Ranging (LIDAR) technology has application in geology, seismology, remote sensing and atmospheric physics.
  • Lasers have been used aboard spacecraft such as in the Cassini-Huygens mission.
  • In astronomy, lasers have been used to create artificial laser guide stars, used as reference objects for adaptive optics telescopes.
  • Spectroscopy
  • Raman spectroscopy
  • Laser induced breakdown spectroscopy (LIBS).
  • Lunar laser ranging – When the Apollo astronauts visited the moon, they planted retroreflector arrays. Laser beams are focused through large telescopes on Earth aimed toward the arrays, and the time taken for the beam to be reflected back to Earth measured to determine the distance between the Earth and Moon with high accuracy.
  • Photochemistry
  • Laser cooling
  • Nuclear fusion
  • Confocal laser scanning microscopy
  • Two-photon excitation microscopy make use of lasers to obtain blur-free images of thick specimens at various depths.
  • Laser capture microdissection use lasers to procure specific cell populations from a tissue section under microscopic visualization.

Defense

  • Directly as an energy weapon
  • On 19 July 2010 an anti-aircraft laser described as the Laser Close-In Weapon System was unveiled at the Farnborough Airshow.[9]
  • The Zeus laser weapon is the first laser and the first energy weapon of any type to be used on a battlefield. It is used for neutralizing mines and unexploded ordnance.
  • Laser Area Defense System.
  • Lockheed Martin’s Area Defense Anti-Munitions[10][11]
  • The Mid-Infrared Advanced Chemical Laser (MIRACL) is an experimental U.S. Navy deuterium fluoride laser and was tested against an Air Force satellite in 1997.
  • In 2011, the U.S. Navy began to test the Maritime Laser Demonstrator (MLD), a laser for use aboard its warships.[12][13]
  • Personnel Halting and Stimulation Response, or PHaSR, is a non-lethal hand-held weapon developed by the United States Air Force [14] Its purpose is to “dazzle” or stun a target. It was developed by Air Force’s Directed Energy Directorate.
  • Tactical High Energy Laser (THEL) is a weaponized deuterium fluoride laser developed in a joint research project by Israel and the U.S. It is designed to shoot down aircraft and missiles. See also National missile defense.
  • The U.S. Air Force’s Airborne Laser, or Advanced Tactical Laser, is a plan to mount a CO2 gas laser or COIL chemical laser on a modified Boeing 747 to shoot down missiles.[15][16]
  • Portable Efficient Laser Testbed (PELT)[17]
  • Laser AirCraft CounterMeasures (ACCM)
  • Defensive countermeasures lasers
  • Lasers to confuse the seeker heads on heat-seeking anti-aircraft missiles.
  • High power boost-phase intercept laser systems use a complex system of lasers to find, track and destroy intercontinental ballistic missiles
  • Chemical laser
  • Mobile Tactical High-Energy Laser weapon system able to track incoming artillery projectiles and cruise missiles
  • Strategic Defense Initiative (SDI, nicknamed “Star Wars”),
  • Nuclear-pumped X-ray laser.
  • X-ray laser
  • Disorientation – weapons to disorient a person. the Thales Green Laser Optical Warner.
  • A target designator a low-power laser pointer used to indicate a target for a precision-guided munition,
  • Laser sight – a small, usually visible-light laser placed on a handgun or a rifle and aligned to emit a beam parallel to the barrel.
  • Eye-targeted lasers A non-lethal laser weapon was developed by the U.S. Air Force to temporarily impair an adversary’s ability to fire a weapon or to otherwise threaten enemy forces.
  • Enforcement use of lasers is for lidar to measure the speed of vehicles.

Medical

  • Cosmetic surgery (removing tattoos, scars, stretch marks, sunspots, wrinkles, birthmarks, and hairs):
  • Laser hair removal. Eye surgery and refractive surgery
  • Soft tissue surgery: CO2, Er:YAG laser
  • Laser scalpel (General surgery, gynecological, urology, laparoscopic)
  • Photobiomodulation (i.e. laser therapy)
  • “No-Touch” removal of tumors, especially of the brain and spinal cord.
  • In dentistry for caries removal, endodontic/periodontic procedures, tooth whitening, and oral surgery

Industrial

  • Lasers used for visual effects during a musical performance. (A laser light show.)
  • Leveling of ceramic tiles floor with a laser device
  • Laser cutting
  • Laser welding
  • Laser drilling
  • Laser marking
  • Laser cladding, a surface engineering process applied to mechanical components for reconditioning, repair work or hardfacing
  • Photolithography
  • Optical communications over optical fiber or in free space
  • Laser peening
  • Guidance systems (e.g., ring laser gyroscopes)
  • Rangefinder / surveying,
  • LIDAR / pollution monitoring,
  • Digital minilabs
  • Barcode readers
  • Laser engraving of printing plate
  • Laser bonding of additive marking materials for decoration and identification,
  • Laser pointers
  • Laser accelerometers
  • OLED display manufacturing
  • Holography
  • Bubblegrams
  • Optical tweezers
  • Writing subtitles onto motion picture films.
  • Power beaming, which is a possible solution to transfer energy to the climber of a Space elevator
  • 3D laser scanners for accurate 3D measurement
  • Laser line levels are used in surveying and construction. Lasers are also used for guidance for aircraft.
  • Laser printers:
  • Diode lasers are used as a lightswitch in industry, with a laser beam and a receiver which will switch on or off
  • Laser alignment
  • Additive manufacturing
  • Plastic welding
  • In consumer electronics, telecommunications, and data communications, lasers are used as the transmitters in optical communications over optical fiber and free space.
  • To store and retrieve data in optical discs
  • Laser lighting displays accompany many music concerts.
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