Laser radiation and its effects on humans
The brilliant foresight of A. Einstein, made by him back in 1917, about the possibility of induced light emission by atoms, was brilliantly confirmed almost half a century when the creation of quantum generators by Soviet physicists N. G. Basov and A. M. Prokhorov. According to the English abbreviation, this device is also called a laser, and the radiation they create is called a laser.
Where do we meet in everyday life with laser radiation? Nowadays, lasers are widely used - these are various fields of technology and medicine, as well as light effects in variety shows and shows. The beauty of iridescent and dancing laser beams made them very attractive for home experimenters and manufacturers of laser gadgets. But how does laser radiation affect human health?
In order to deal with these issues, it is necessary to recall what laser radiation is. To do this, "let's fast forward" to a physics lesson in grade 10 and talk about light quanta.
What is laser radiation
Ordinary light is born in atoms. Laser radiation is the same. However, with other physical processes and as a result of exposure to an external electromagnetic field. Therefore, the laser radiation is stimulated.
Laser radiation is electromagnetic waves propagating almost parallel to each other. Therefore, the laser beam has a sharp directivity, an extremely small scattering angle and a very significant intensity of exposure to the irradiated surface.
What is the difference between laser radiation and, for example, incandescent lamp radiation? An incandescent lamp is a man-made light source that emits electromagnetic waves, in contrast to laser radiation, in a wide spectral range with a propagation angle of about 360 degrees.
The effect of laser radiation on the human body
The possibility of extremely diverse use of quantum generators has prompted specialists from various fields of medicine to come to grips with the effects of laser radiation on the human body. It was found that this type of radiation has the following properties:
when working with laser radiation sources, damaging factors can be either direct (from the installation itself), or scattered, as well as reflected radiation;
- the degree of damage depends on the parameters of the electromagnetic wave and the location of the irradiated tissue;
- The energy absorbed by these tissues can cause a number of negative effects - heat, light, etc.
The sequence of damage in the biological action of laser radiation is as follows:
- a sharp rise in temperature, followed by a burn;
- this is followed by boiling of interstitial as well as cellular fluid;
- The resulting vapor creates enormous pressure, resulting in an explosion and a shock wave that destroys the surrounding tissues.
At small and medium radiation intensities, the skin is particularly affected. With a stronger effect, the lesions on the skin appear as edemas, hemorrhages and dead areas. But internal tissues undergo significant changes. And the greatest danger comes from direct and specularly reflected radiation. It also causes pathological changes in the work of the most important systems of the body.
Let us dwell on the effects of laser radiation on the organs of vision.
Short pulses of radiation generated by a laser cause severe damage to the retina, cornea, iris and lens of the eye.
There are 3 reasons for this.
- For such short periods of time the pulse duration (0.1 s) does not have time to trigger the protective blinking reflex.
In addition, the cornea and lens of the eye are extremely easily vulnerable organs.
- The optical system of the eye also contributes negatively to damage to the organs of vision, focusing laser radiation on the fundus. The point of laser radiation caught in the retinal vessel may block it. Since there are no pain receptors there, the retinal damage is unnoticeable at first. But, when the area scorched by the laser beam becomes large enough, the images of objects that fall on it disappear.
Spasms and swelling of the eyelids, eye pain, clouding and retinal hemorrhage are characteristic symptoms of eye damage. After damage, retinal cells are not restored.
The intensity of radiation that causes damage to the organs of vision has a lower level than the radiation that causes damage to the skin. Any infrared lasers, as well as devices that emit radiation in the visible spectrum with a power of more than 5 MW, can be dangerous.
The dependence of the influence on a person of laser radiation on his spectrum
Remarkable scientists from different countries who worked on the creation of a quantum generator could not even predict what widespread use their child would find in various spheres of life. But each of these areas will require specific, specific wavelengths.
Why does the wavelength of laser radiation depend? It is determined by nature, more precisely, by the electronic structure of the working fluid (the medium where this radiation is generated). There are various solid-state and gas lasers. These miracle rays can belong to the ultraviolet, apparently (often red) and infrared part of the spectrum. Their range is in the range of 180 nm. and up to 30 microns.
The nature of the effect of laser radiation on the human body depends largely on the wavelength. Our vision is about 30 times more sensitive to green than to red. Consequently, we will respond to the green laser faster. In this sense, it is safer than red.
Protection against laser radiation at work
There is a huge category of people whose professional activities are directly or indirectly related to quantum generators. For them there are strict regulations and standards for protection against laser radiation. They include general and individual protection measures, depending on the degree of danger that this laser installation represents for all structures of the human body.
In total there are 4 hazard classes that the manufacturer must specify. Danger to the human body are lasers 2,3 and 4 classes.
Collective means of protection from laser radiation are protective screens and housings, light guides, television and telemetry tracking methods, alarm systems and interlocks, as well as fencing of the zone with irradiation exceeding the maximum permissible level.
Individual protection of employees is provided with a special set of clothes. For eye protection, it is imperative to wear glasses with a special coating.
The best prevention of laser radiation is compliance with the rules of operation and protection, as well as timely medical examination.
Laser protection for users of laser gadgets
Uncontrolled use of homemade lasers, lamps, light pointers, laser flashlights poses a serious danger to others. To avoid tragic consequences, remember:
- "Games" with the use of lasers are permissible only where there are no outsiders;
- rays reflected from glass, buckles and other objects are very dangerous;
- a beam of even low intensity, when caught in the eyes of a driver, athlete, air transport pilot, can cause a tragedy;
- Store laser gadgets out of the reach of children and adolescents;
- it is possible to send rays to the sky only at low cloud cover, since there is no air transport at these heights;
- it is completely unacceptable to look into the lens of a laser source;
- protective eyewear must match the laser wavelength.
Quantum generators and any laser gadgets pose a potential threat to their owners and those around them. And only careful observance of security measures will allow you to enjoy these achievements without harm to yourself and your friends.