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There are many scientific, military, medical and commercial laser applications which have been developed since the invention of the laser in the 1958. The coherency, high monochromaticity, and ability to reach extremely high powers are all properties which allow for these specialized applications. In Physics, coherence is a property of waves that enables stationary (i Monochrome comes from the Greek μονόχρωμος ( monochromos) meaning “of one color” which is a combination In Physics, power (symbol P) is the rate at which work is performed or energy is transmitted or the amount of energy required or expended for


Contents

Scientific

In science, lasers are used in many ways, including:

Spectroscopy

Most types of laser are an inherently pure source of light; they emit near-monochromatic light with a very well defined range of wavelengths. Monochrome comes from the Greek μονόχρωμος ( monochromos) meaning “of one color” which is a combination In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. By careful design of the laser components, the purity of the laser light (measured as the "linewidth") can be improved more than the purity of any other light source. The spectral linewidth characterizes the width of a Spectral line, such as in the electromagnetic emission spectrum of an atom or the Frequency spectrum This makes the laser a very useful source for spectroscopy. Spectroscopy was originally the study of the interaction between Radiation and Matter as a function of Wavelength (λ The high intensity of light that can be achieved in a small, well collimated beam can also be used to induce a nonlinear optical effect in a sample, which makes techniques such as Raman spectroscopy possible. Raman spectroscopy (pronounced S— is a spectroscopic technique used in Condensed matter physics and Chemistry to study vibrational rotational and Other spectroscopic techniques based on lasers can be used to make extremely sensitive detectors of various molecules, able to measure molecular concentrations in the parts-per-trillion (ppt) level. Due to the high power densities achievable by lasers, beam-induced atomic emission is possible: this technique is termed Laser induced breakdown spectroscopy (LIBS). Laser-induced breakdown spectroscopy (LIBS is a type of atomic emission Spectroscopy which utilises a highly energetic Laser pulse as the excitation source

Lasers may also be indirectly used in spectroscopy as a micro-sampling system, a technique termed Laser ablation (LA), which is typically applied to ICP-MS apparatus resulting in the powerful LA-ICP-MS. Ablation is defined as the removal of material from the surface of an object by Vaporization, Chipping, or other erosive processes ICP-MS ( Inductively coupled plasma mass spectrometry) is a type of Mass spectrometry that is highly sensitive and capable of the determination of a range of Metals

Lunar laser ranging

Main article: Lunar laser ranging experiment

When the Apollo astronauts visited the moon, they planted retroreflector arrays to make possible the Lunar Laser Ranging Experiment. The ongoing Lunar Laser Ranging Experiment measures the distance between the Earth and the Moon using laser ranging. A retroreflector (sometimes called a retroflector) is a device or surface that reflects light back to its source with a minimum scattering of light The ongoing Lunar Laser Ranging Experiment measures the distance between the Earth and the Moon using laser ranging. 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 precision. A telescope is an instrument designed for the observation of remote objects and the collection of Electromagnetic radiation.

Material processing

Laser cutting, laser welding, laser brazing, laser bending, laser engraving or marking, laser cleaning, etc.

Photochemistry

Some laser systems, through the process of modelocking, can produce extremely brief pulses of light - as short as picoseconds or femtoseconds (10-12 - 10-15 seconds). Mode-locking is a technique in Optics by which a Laser can be made to produce pulses of Light of extremely short duration on the order of picoseconds (10-12s The second ( SI symbol s) sometimes abbreviated sec, is the name of a unit of Time, and is the International System of Units Such pulses can be used to initiate and analyse chemical reactions, a technique known as photochemistry. The short pulses can be used to probe the process of the reaction at a very high temporal resolution, allowing the detection of short-lived intermediate molecules. This method is particularly useful in biochemistry, where it is used to analyse details of protein folding and function. Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as

Laser cooling

A technique that has had recent success is laser cooling. This involves atom trapping, a method where a number of atoms are confined in a specially shaped arrangement of electric and magnetic fields. In Physics, the space surrounding an Electric charge or in the presence of a time-varying Magnetic field has a property called an electric field (that can In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges Shining particular wavelengths of laser light at the ions or atoms slows them down, thus cooling them. As this process is continued, they all are slowed and have the same energy level, forming an unusual arrangement of matter known as a Bose-Einstein condensate. A Bose–Einstein condensate (BEC is a State of matter of Bosons confined in an external Potential and cooled to Temperatures very near to


Nuclear fusion

Some of the world's most powerful and complex arrangements of multiple lasers and optical amplifiers are used to produce extremely high intensity pulses of light of extremely short duration. These pulses are arranged such that they impact pellets of tritium-deuterium simultaneously from all directions, hoping that the squeezing effect of the impacts will induce atomic fusion in the pellets. Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth In Physics and Nuclear chemistry, nuclear fusion is the process by which multiple- like charged atomic nuclei join together to form a heavier nucleus This technique, known as "inertial confinement fusion", so far has not been able to achieve "breakeven", that is, so far the fusion reaction generates less power than is used to power the lasers, but research continues. Inertial confinement fusion ( ICF) is a process where Nuclear fusion reactions are initiated by heating and compressing a fuel target typically in the form of

Microscopy

Confocal laser scanning microscopy and Two-photon excitation microscopy make use of lasers to obtain blur-free images of thick specimens at various depths. Confocal laser scanning microscopy ( CLSM or LSCM) is a technique for obtaining high- resolution optical images Two-photon excitation microscopy is a Fluorescence imaging technique that allows imaging living tissue up to a depth of one millimeter

Military

Military uses of lasers include applications such as target designation and ranging, defensive countermeasures, communications and directed energy weapons. A military is an Organization authorized by its Nation to use force usually including use of Weapons in defending its Country (or by attacking There are many scientific military medical and commercial laser applications which have been developed since the invention of the laser in the 1958 A directed-energy weapon ( DEW) is a type of weapon that emits Energy in an aimed direction without the means of a Projectile.

Defensive countermeasures

Defensive countermeasure applications can range from compact, low power infrared countermeasures to high power, airborne laser systems. IR countermeasure systems use 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. In this type of system a chemical laser, one in which the laser operation is powered by an energetic chemical reaction, is used as the main weapon beam (see Airborne Laser). A chemical laser is a Laser that obtains its energy from a Chemical reaction. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout The Mobile Tactical High-Energy Laser (MTHEL) is another defensive laser system under development; this is envisioned as a field-deployable weapon system able to track incoming artillery projectiles and cruise missiles by radar and destroy them with a powerful deuterium fluoride laser. The Tactical High-Energy Laser, or THEL, is a Laser developed for Military use also known as the Nautilus laser system. Artillery (from French artillerie) is a military Combat Arm which employs any apparātus machine A cruise missile is a guided Missile that carries an explosive payload and uses a lifting wing and a propulsion system usually a Jet engine, to allow Radar is a system that uses electromagnetic waves to identify the range altitude direction or speed of both moving and fixed objects such as Aircraft, ships The hydrogen fluoride laser is an Infrared Chemical laser. It is capable of delivering continuous output power in the Megawatt range

Another example of direct use of a laser as a defensive weapon was researched for the Strategic Defense Initiative (SDI, nicknamed "Star Wars"), and its successor programs. The Strategic Defense Initiative (SDI was a proposal by US President Ronald Reagan on March 23, 1983 to use ground and space-based systems to protect Star Wars is an epic Space opera franchise initially conceived by George Lucas during the 1970s and significantly expanded This project would use ground-based or space-based laser systems to destroy incoming intercontinental ballistic missiles (ICBMs). The practical problems of using and aiming these systems were many; particularly the problem of destroying ICBMs at the most opportune moment, the boost phase just after launch. This would involve directing a laser through a large distance in the atmosphere, which, due to optical scattering and refraction, would bend and distort the laser beam, complicating the aiming of the laser and reducing its efficiency. Refraction is the change in direction of a Wave due to a change in its Speed.

Another idea to come from the SDI project was the nuclear-pumped X-ray laser. This was essentially an orbiting atomic bomb, surrounded by laser media in the form of glass rods; when the bomb exploded, the rods would be bombarded with highly-energetic gamma-ray photons, causing spontaneous and stimulated emission of X-ray photons in the atoms making up the rods. A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena Spontaneous emission is the process by which a light source such as an Atom, Molecule, Nanocrystal or nucleus in an Excited state In Optics, stimulated emission is the process by which an electron perturbed by a Photon having the correct energy may drop to a lower Energy level resulting X-radiation (composed of X-rays) is a form of Electromagnetic radiation. This would lead to optical amplification of the X-ray photons, producing an X-ray laser beam that would be minimally affected by atmospheric distortion and capable of destroying ICBMs in flight. The X-ray laser would be a strictly one-shot device, destroying itself on activation. Some initial tests of this concept were performed with underground nuclear testing; however, the results were not encouraging. Underground nuclear testing refers to test detonations of Nuclear weapons that are performed underground Research into this approach to missile defense was discontinued after the SDI program was cancelled.

The United States Air Force has experimented with using lasers combined with high-altitude airships as a potential means for a missile defense shield but also as a means to destroy enemy spacecraft or satellites in low-earth orbit. Terminology In some countries airships are also known as dirigibles from the French (fr ''diriger'' to direct plus -ible) meaning "directable" This article is about artificial satellites For natural satellites also known as moons see Natural satellite. In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star For more information, see Evolutionary Air and Space Global Laser Engagement. The Evolutionary Air and space Global Laser Engagement ( EAGLE) is a new plan being developed by the United States Air Force. According to a 2005 report issued by the Pentagon, China is developing a laser that could blind low Earth orbit satellites. A Low Earth Orbit (LEO is generally defined as an Orbit within the locus extending from the Earth’s surface up to an altitude of 2000 km [1]

In the most recent edition of Popular Science (the April 2008 issue), there is an article showcasing a new combat laser, the Boeing Advanced Tactical Laser Beam, which will be carried in a large aircraft (it is shown carried in a C-130) and fired at large targets (vehicles or buildings. ) It is currently being tested at Kirtland Air Force Base in New Mexico. The laser itself is a chemical laser, and weighs 40,000 pounds. The range is reported to be 5 miles, and it can rapidly strike targets (it uses rapid-fire rather than a continuous beam to minimize the risk of friendly fire. ) However, the prototype cost $200 million, making it doubtful that this will be put to widespread use. Barring the cost, it is expected to be in battle within five years. There is also talk of development of smaller versions to fit in smaller vehicles.

Targeting

Ranging

Main article: Laser range-finder

A laser range-finder is a device consisting of a pulsed laser and a light detector. By measuring the time taken for light to reflect off a far object, and knowing the speed of light, the range to the object can be found. A laser rangefinder is thus a simple form of LIDAR. LIDAR ( Li ght D etection a nd R anging is an optical remote sensing technology that measures properties of scattered light to find range and/or The distance to the target can then be used to aim a weapon such as a tank's main gun. A tank is a tracked, Armoured fighting vehicle designed for Front-line combat which combines Operational mobility and tactical

Target designator

Main article: Laser designator
A target designator
A target designator

Another military use of lasers is as a laser target designator. A laser designator is a Laser light source which is used to illuminate a target This is a low-power laser pointer used to indicate a target for a precision-guided munition, typically launched from an aircraft. A laser pointer is a portable pen-sized Laser designed to be held in the hand and most commonly used to project a point of light to highlight items of interest during a The guided munition adjusts its flight-path to home in to the laser light reflected by the target, enabling a great precision in aiming. The beam of the laser target designator is set to a pulse rate that matches that set on the guided munition to ensure munitions strike their designated targets and do not follow other laser beams which may be in use in the area. The laser designator can be shone onto the target by an aircraft or nearby infantry. Lasers used for this purpose are usually infrared lasers, so the enemy cannot easily detect the guiding laser light. Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of

Military/police applications

Laser sight

Revolver equipped with laser sight.
Revolver equipped with laser sight.

The laser has in most military applications been used as a tool to enhance the targeting of other weapon systems. For example, a laser sight is a small, usually visible-light laser placed on a handgun or rifle aligned to emit a beam parallel to the barrel. Since a laser beam by definition has low divergence, the laser light appears as a small spot even at long distances; the user simply places the spot on the desired target and the barrel of the gun is aligned.

Most laser sights use a red laser diode. Others use an infrared diode to produce a dot invisible to the naked human eye but detectable with night vision devices. In the late 1990s, green diode pumped solid state laser (DPSS) laser sights (532 nm) became available. Diode-pumped solid-state (DPSS lasers are Solid-state lasers made by pumping a solid Gain medium, for example a Ruby or a Crystal Modern laser sights are small and light enough for attachment to the firearms.

In 2007, LaserMax, a company specializing in manufacturing lasers for military and police firearms, introduced the first mass-production green laser available for small arms. [2] This laser mounts to the underside of a handgun or long arm on the accessory rail. The green laser is supposed to be more visible than the red laser in bright lighting conditions.

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. This unit illuminates an opponent with harmless low-power laser light and can have the effect of dazzling or disorienting the subject or causing them to flee. There remains the possibility of using lasers to blind, since this requires much lower power levels, and is easily achievable in a man portable unit. However, most nations regard the deliberate permanent blinding of the enemy as forbidden by the rules of war (see Protocol on Blinding Laser Weapons). The law of war (also law of armed conflict, LOAC) is Law concerning acceptable practices relating to war The Protocol on Blinding Laser Weapons, Protocol IV of the 1980 Convention on Certain Conventional Weapons, was issued by the United Nations on 13 October

In addition to the applications that crossover with military applications, a widely known law enforcement use of lasers is for lidar to measure the speed of vehicles. LIDAR ( Li ght D etection a nd R anging is an optical remote sensing technology that measures properties of scattered light to find range and/or

Medical

Industrial and commercial

Lasers used for visual effects during a musical performance. (A laser light show.)
Lasers used for visual effects during a musical performance. (A laser light show. A laser lighting display or laser Light show involves the use of Laser light to entertain an audience )

In consumer electronics, telecommunications, and data communications, lasers are used as the transmitters in optical communications over optical fiber and free space. Additive Manufacturing is the process of making a Product by adding Layers in a relatively efficient way such that there is little waste or reduction of materials Consumer electronics include electronic equipment intended for everyday use Computer networking is the Engineering Discipline concerned with communication between Computer systems or devices Networking routers Optical communication is any form of Telecommunication that uses Light as the transmission medium An optical fiber (or fibre) is a Glass or Plastic fiber that carries Light along its length In Telecommunications Free Space Optics (FSO is an Optical communication technology that uses light propagating in free space to transmit data between two points

Distinguish from

References

  1. ^ USATODAY.com - Report: China working on anti-satellite systems
  2. ^ LaserMax Introduces the UniMax Green Laser for Firearms
  3. ^ Cinetyp Hollywood - film subtitles, video subtitles, DVD subtitles, film overlay, video, film, overlay, foreign subtitles, closed captioning, open captioning, spotting lists

Images

Lasers were used in the 2005 Classical Spectacular concert

A laser harp

The surface of a test target is instantly vaporized and bursts into flame upon irradiation by a high power continuous wave carbon dioxide laser emitting tens of kilowatts of far infrared light. A laser harp is an Electronic musical instrument consisting of several Laser beams to be blocked in analogy with the plucking of the strings of a Harp, The carbon dioxide laser ( CO2 laser) was one of the earliest Gas lasers to be developed (invented by Kumar Patel of Bell Labs in 1964 Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of Note the operator is standing behind sheets of plexiglas, which is opaque in the far infrared. Poly(methyl methacrylate ( PMMA) or poly(methyl 2-methylpropenoate is a Thermoplastic and transparent Plastic.

External links

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