- Laser Acronym Explanation | Merriam-Webster
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New technologies such as high-power fiber laser and diode laser have been introduced in the fiber laser market. Dimed Laser is a professional manufacturer of surgical laser systems and equipment with products covering ENT laser , PLDD laser , skin laser machine, class IV laser therapy, dental laser machine, veterinary laser equipment, toenail laser and so forth. In the same period, the industrial laser and related products market in China reached This list is incomplete ; you can help by adding missing items.
August List of laser articles List of laser types List of laser applications Laser acronyms. These lasers are also commonly frequency doubled , tripled or quadrupled to produce nm green, visible , nm and nm UV beams, respectively.
Frequency-doubled diode-pumped solid-state DPSS lasers are used to make bright green laser pointers. Ytterbium , holmium , thulium , and erbium are other common "dopants" in solid-state lasers. They are potentially very efficient and high powered due to a small quantum defect.
Extremely high powers in ultrashort pulses can be achieved with Yb:YAG. Holmium -doped YAG crystals emit at nm and form an efficient laser operating at infrared wavelengths strongly absorbed by water-bearing tissues.
The Ho-YAG is usually operated in a pulsed mode, and passed through optical fiber surgical devices to resurface joints, remove rot from teeth, vaporize cancers, and pulverize kidney and gall stones. Titanium -doped sapphire Ti:sapphire produces a highly tunable infrared laser, commonly used for spectroscopy. It is also notable for use as a mode-locked laser producing ultrashort pulses of extremely high peak power.
Thermal limitations in solid-state lasers arise from unconverted pump power that heats the medium. Diode-pumped thin disk lasers overcome these issues by having a gain medium that is much thinner than the diameter of the pump beam. This allows for a more uniform temperature in the material.
Thin disk lasers have been shown to produce beams of up to one kilowatt. Solid-state lasers or laser amplifiers where the light is guided due to the total internal reflection in a single mode optical fiber are instead called fiber lasers.
Guiding of light allows extremely long gain regions providing good cooling conditions; fibers have high surface area to volume ratio which allows efficient cooling. In addition, the fiber's waveguiding properties tend to reduce thermal distortion of the beam.
Erbium and ytterbium ions are common active species in such lasers. Quite often, the fiber laser is designed as a double-clad fiber. This type of fiber consists of a fiber core, an inner cladding and an outer cladding. The index of the three concentric layers is chosen so that the fiber core acts as a single-mode fiber for the laser emission while the outer cladding acts as a highly multimode core for the pump laser.
This lets the pump propagate a large amount of power into and through the active inner core region, while still having a high numerical aperture NA to have easy launching conditions.
Pump light can be used more efficiently by creating a fiber disk laser , or a stack of such lasers. This effect is called photodarkening.
In bulk laser materials, the cooling is not so efficient, and it is difficult to separate the effects of photodarkening from the thermal effects, but the experiments in fibers show that the photodarkening can be attributed to the formation of long-living color centers. Photonic crystal lasers are lasers based on nano-structures that provide the mode confinement and the density of optical states DOS structure required for the feedback to take place.
Semiconductor lasers are diodes which are electrically pumped. Recombination of electrons and holes created by the applied current introduces optical gain. Reflection from the ends of the crystal form an optical resonator, although the resonator can be external to the semiconductor in some designs. Commercial laser diodes emit at wavelengths from nm to nm. Laser diodes are also frequently used to optically pump other lasers with high efficiency.
The highest power industrial laser diodes, with power up to 20 kW, are used in industry for cutting and welding. These devices can generate high power outputs with good beam quality, wavelength-tunable narrow- linewidth radiation, or ultrashort laser pulses.
Vertical cavity surface-emitting lasers VCSELs are semiconductor lasers whose emission direction is perpendicular to the surface of the wafer. VCSEL devices typically have a more circular output beam than conventional laser diodes. Quantum cascade lasers are semiconductor lasers that have an active transition between energy sub-bands of an electron in a structure containing several quantum wells.
The development of a silicon laser is important in the field of optical computing. Silicon is the material of choice for integrated circuits , and so electronic and silicon photonic components such as optical interconnects could be fabricated on the same chip.
Unfortunately, silicon is a difficult lasing material to deal with, since it has certain properties which block lasing. However, recently teams have produced silicon lasers through methods such as fabricating the lasing material from silicon and other semiconductor materials, such as indium III phosphide or gallium III arsenide , materials which allow coherent light to be produced from silicon.
These are called hybrid silicon laser. Recent developments have also shown the use of monolithically integrated nanowire lasers directly on silicon for optical interconnects, paving the way for chip level applications. Dye lasers use an organic dye as the gain medium. The wide gain spectrum of available dyes, or mixtures of dyes, allows these lasers to be highly tunable, or to produce very short-duration pulses on the order of a few femtoseconds.
Although these tunable lasers are mainly known in their liquid form, researchers have also demonstrated narrow-linewidth tunable emission in dispersive oscillator configurations incorporating solid-state dye gain media. In their most prevalent form these solid state dye lasers use dye-doped polymers as laser media. Free-electron lasers , or FELs, generate coherent, high power radiation that is widely tunable, currently ranging in wavelength from microwaves through terahertz radiation and infrared to the visible spectrum, to soft X-rays.
They have the widest frequency range of any laser type. While FEL beams share the same optical traits as other lasers, such as coherent radiation, FEL operation is quite different.
Unlike gas, liquid, or solid-state lasers, which rely on bound atomic or molecular states, FELs use a relativistic electron beam as the lasing medium, hence the term free-electron. The pursuit of a high-quantum-energy laser using transitions between isomeric states of an atomic nucleus has been the subject of wide-ranging academic research since the early s. Much of this is summarized in three review articles. While many scientists remain optimistic that a breakthrough is near, an operational gamma-ray laser is yet to be realized.
In September , the BBC News reported that there was speculation about the possibility of using positronium annihilation to drive a very powerful gamma ray laser. David Cassidy of the University of California, Riverside proposed that a single such laser could be used to ignite a nuclear fusion reaction, replacing the banks of hundreds of lasers currently employed in inertial confinement fusion experiments.
Space-based X-ray lasers pumped by a nuclear explosion have also been proposed as antimissile weapons. Living cells have been used to produce laser light.
The cells were then placed between two 20 micrometer wide mirrors, which acted as the laser cavity. When the cell was illuminated with blue light, it emitted intense, directed green laser light. Like astrophysical masers , irradiated planetary or stellar gases may amplify light producing a natural laser.
When lasers were invented in , they were called "a solution looking for a problem". Fiber-optic communication using lasers is a key technology in modern communications, allowing services such as the Internet. The first widely noticeable use of lasers was the supermarket barcode scanner , introduced in The laserdisc player, introduced in , was the first successful consumer product to include a laser but the compact disc player was the first laser-equipped device to become common, beginning in followed shortly by laser printers.
Lasers have many uses in medicine, including laser surgery particularly eye surgery , laser healing photobiomodulation therapy , kidney stone treatment, ophthalmoscopy , and cosmetic skin treatments such as acne treatment, cellulite and striae reduction, and hair removal.
Lasers are used to treat cancer by shrinking or destroying tumors or precancerous growths. They are most commonly used to treat superficial cancers that are on the surface of the body or the lining of internal organs. They are used to treat basal cell skin cancer and the very early stages of others like cervical , penile , vaginal , vulvar , and non-small cell lung cancer. Laser therapy is often combined with other treatments, such as surgery , chemotherapy , or radiation therapy.
Laser-induced interstitial thermotherapy LITT , or interstitial laser photocoagulation , uses lasers to treat some cancers using hyperthermia, which uses heat to shrink tumors by damaging or killing cancer cells. Lasers are more precise than traditional surgery methods and cause less damage, pain, bleeding , swelling, and scarring.
A disadvantage is that surgeons must acquire specialized training and thus it will likely be more expensive than other treatments. A laser weapon is a laser that is used as a directed-energy weapon. In recent years, some hobbyists have taken an interest in lasers. Due to the cost of lasers, some hobbyists use inexpensive means to obtain lasers, such as salvaging laser diodes from broken DVD players red , Blu-ray players violet , or even higher power laser diodes from CD or DVD burners. Hobbyists have also used surplus lasers taken from retired military applications and modified them for holography.
Pulsed ruby and YAG lasers work well for this application. Different applications need lasers with different output powers. Lasers that produce a continuous beam or a series of short pulses can be compared on the basis of their average power.
Lasers that produce pulses can also be characterized based on the peak power of each pulse. The peak power of a pulsed laser is many orders of magnitude greater than its average power. The average output power is always less than the power consumed. Even the first laser was recognized as being potentially dangerous. Theodore Maiman characterized the first laser as having a power of one "Gillette" as it could burn through one Gillette razor blade.
Today, it is accepted that even low-power lasers with only a few milliwatts of output power can be hazardous to human eyesight when the beam hits the eye directly or after reflection from a shiny surface. At wavelengths which the cornea and the lens can focus well, the coherence and low divergence of laser light means that it can be focused by the eye into an extremely small spot on the retina , resulting in localized burning and permanent damage in seconds or even less time.
Lasers are usually labeled with a safety class number, which identifies how dangerous the laser is:. The indicated powers are for visible-light, continuous-wave lasers. For pulsed lasers and invisible wavelengths, other power limits apply. People working with class 3B and class 4 lasers can protect their eyes with safety goggles which are designed to absorb light of a particular wavelength. Infrared lasers with wavelengths longer than about 1.
The label "eye-safe" can be misleading, however, as it applies only to relatively low power continuous wave beams; a high power or Q-switched laser at these wavelengths can burn the cornea, causing severe eye damage, and even moderate power lasers can injure the eye. Lasers can be a hazard to both civil and military aviation, due to the potential to temporarily distract or blind pilots. See Lasers and aviation safety for more on this topic.
Cameras based on charge-coupled devices may actually be more sensitive to laser damage than biological eyes. From Wikipedia, the free encyclopedia.
Device which emits light via optical amplification. For other uses, see Laser disambiguation. For uses of "Laze", see Laze. Main article: Laser construction.
Gain medium Laser pumping energy High reflector Output coupler Laser beam. This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. May Learn how and when to remove this template message.
See also: Laser science. Main article: Stimulated emission. Main article: Pulsed laser. Main article: Q-switching. Main article: Mode locking. Main article: Maser. Further information: List of laser types.
Main article: Gas laser. Main article: Fiber laser. Main article: Semiconductor lasers. Main article: List of applications for lasers.
Main articles: Laser medicine and Lasers in cancer treatment. Main article: Laser weapon. This article should include a summary of Laser weapon. See Wikipedia:Summary style for information on how to incorporate it into this article's main text. December Main article: Laser safety.
Left: European laser warning symbol required for Class 2 lasers and higher. Right: US laser warning label, in this case for a Class 3B laser. These cookies ensure basic functionalities and security features of the website, anonymously.
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