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Light is very important to human life, a type of light invented in the 20th century with high practical application today is the laser. So what is a laser? Types of lasers, effects and harms of lasers like? This article lassho.edu.vn will answer these questions!
What is a laser?
Laser ( Light A mplification by S timulated E mission of R adiation): is understood as the amplification of light by stimulated radiation.
A laser is an artificial light source obtained by amplifying light by radiation emitted under conditions of highly active particles of the material medium.
Structure and principle of laser emission
2.1 Laser construction
A standard laser lamp or device that emits a laser beam will have three basic components :
– Laser material or active medium : The medium in which the active ingredients are excited by external energy sources to create a reversal of the electron movement current. In the amplification medium, spontaneous and stimulated emission of photon quantum particles takes place, resulting in optical amplification. Semiconductors, organic dyes, gases, solid materials are commonly used as luminescent materials.
The active medium determines the wavelength and other properties of the emitted laser.
– External energy source (light, electricity) : is an energy source large enough to provide an impact on charged particles in the active environment and emit radiation to excite the system.
– Optical Resonance Chamber : Contains reflectors and semi-reflectors at both ends that make photons collide continuously with the active substance many times, creating a large density of photons.
2.2 Principle of laser emission
– Under the influence of a large potential difference, the electrons of the active medium move from a low energy level to a high energy level, creating an inverse state of electron density.
At high energies, some electrons will randomly fall to low energies, releasing light called photons.
– These photons will radiate in different directions from an atom, collide with other atoms, excite the electrons in these atoms to fall further, generating more photons of the same frequency, phase and direction of flight. , creating a chain reaction that amplifies the flow of light.
– Photon particles are reflected back and forth many times in the material, thanks to mirrors to increase light amplification efficiency.
– Some photons escape thanks to a semi-plated mirror at one end of the material. The emitted light is the laser.
Types of lasers
Based on the active ingredients, we can divide the lasers into the following types:
– Solid laser: Currently, there are about 200 solid substances that can be used as the laser active medium, for example: glass materials, vitreous,… The laser has high application popularity today and is discovered. the first is the ruby laser.
– Liquid laser: the liquid that is used as the active medium is called liquid laser. Pulsed dye lasers are the basic example of this type of laser, they use organic dyes as the active medium.
– Gas laser: The type of laser in which an electric current is discharged in a gaseous medium is used as the active medium is called a gas laser. This type of laser is applied in cases where high beam and coherent laser light is required.
– Semiconductor laser: also known as diode laser and plays an important role in life such as: reading Compact discs, laser printers, making pens, anti-theft machines, …
This type of laser differs from semiconductor lasers in that solid lasers use light energy as the pump source and semiconductor lasers use electricity as the pump source . At present, semiconductor lasers have low cost, compact size and low energy consumption.
Effects and harmful effects of laser in life
4.1 Applications of laser in life
Medical applications: Lasers are used as scalpels in surgery because of their ease of control, depth control and small contact area. Lasers can be used to restore vision for myopia cases, combined with optical fibers to treat retinal diseases, diagnose cancer, ….
Applications in cosmetology: In this field, lasers also have wide applications such as skin resurfacing, skin tightening, and treatment of accelerated skin lesions (freckles, age spots, moles). , tattoo removal,…
Applications in other industries : Hard materials such as quartz and glass can be used for laser cutting. Laser guns are used in sales industries such as barcode scanning, in construction for measuring applications in distance meters, laser leveling machines, …
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Applications in science and technology : Lasers are used to study the Brownian motion of particles. Lasers can measure pollutants in the air,…
Military Application : Laser range finder is used to determine the object base distance, laser stunner is used as a covert illuminator to track the object with high accuracy when scouting. close to night,…
4.2 Harmful effects of laser
Despite being widely used, lasers also have some caveats because they can cause great harm to us.
– Do not shine the laser directly into the eyes because the rays can damage the retina, causing damage to the eyes.
– Do not use laser-lit toys intended for children.
– Check the product’s information according to the manufacturer’s information in accordance with international standards on the appropriate safety of lasers in the product.
The last article is the basic information about lasers as well as their effects and harmful effects. If you have any questions, please leave them in the comments section for answers!
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